Back in 1918 there was just one supposed billionaire on the planet, an assumption that has since been called into question. Nowadays a total of 2,153 people around the world boast a net worth of 10 figures or more. Looking back over the past 100 years, we reveal how the number of billionaires has changed and chart the evolution of the planet's most exclusive club.

On 29 September 1916 newspapers across America proclaimed John D. Rockefeller the first ever dollar billionaire thanks to a surge in the share price of his company Standard Oil. According to news reports at the time, the magnate's 247,692 shares had risen in value to $499 million. Factoring in the Gilded Age tycoon's remaining assets, the press declared Rockefeller a bona fide billionaire.

Forbes began tracking the wealth of America's richest people back in 1918, though the Forbes 400 List of the wealthiest people in the country wasn't published until 1982, while the magazine's round-up of the world's most moneyed individuals debuted in 1987. Rockefeller was at the top of Forbes' first list in 1918 with a net worth of $1.2 billion, the equivalent of $17 billion (£13.3bn) in today's money. He was followed by Henry Clay Frick (pictured), whose wealth was put at $225 million, which would be $3.8 billion (£3bn) today.

The 10-figure estimate was dismissed as a gross exaggeration by Rockefeller's son, and over the years a slew of historians has cast doubt on it with one prominent biographer arguing that the oil magnate's wealth peaked in 1913 at $900 million. These days most historians in the know consider another American industrialist the first ever dollar billionaire.

That individual is none other than automotive pioneer Henry Ford. Long dubbed 'American's second billionaire', the man who brought the world its first mass-produced car attained a net worth surpassing the billion-dollar mark in 1925. Interestingly, Ford's wealth was estimated by Forbes in 1918 at just $100 million.

During the Depression years of the 1930s, Henry Ford's wealth was probably surpassed by Andrew Mellon, the banker and industrialist who was US Secretary of the Treasury from 1921 to 1932. Up until his death in 1937, the billionaire was considered America's richest person and is likely to have been the most moneyed individual in the world at that time.

Although it isn't conclusive given no definitive list of global billionaires was published until 1987,  it is generally thought that after Mellon's death Henry Ford was the sole dollar billionaire from 1937 to 1940. Oil tycoon H. L. Hunt had joined the world's most exclusive club by 1940 according to Texas Monthly, after he gained ownership of America's most important oil field. At this point, Hunt was expanding his business's operations into the Middle East.

Henry Ford died in 1947, leaving Hunt the world's only billionaire for a time before he was overtaken by another oil magnate, J. Paul Getty. Fortune published its first round-up of the wealthiest Americans in 1957, placing Getty in position number one. Fortune considered him the world's richest private individual, while the magazine put H. L. Hunt's wealth at between $400-$700 million.

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During the Swinging Sixties the wealth of another American tycoon broke the billion-dollar mark. Reclusive magnate Howard Hughes, the renowned aircraft pioneer, movie producer, mine owner and casino boss, attained the magic figure during this decade, joining J. Paul Getty in the planet's most rarefied club.

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As far as we can ascertain there were few confirmed dollar billionaires outside the US in the 1960s. Possible candidates at this time for the 10-figure-plus club include West Germany's richest man Friedrich Flick, who was a convicted Nazi war criminal, and Greek shipping magnate Aristotle Onassis (pictured).

The 1970s saw something of an explosion in the number of billionaires worldwide. Americans such as John Donald MacArthur, David Rockefeller, Daniel Keith Ludwig and Ross Perot (briefly) joined the ranks, as did several Middle Eastern oil tycoons, Saudi arms dealer Adnan Khashoggi (pictured), France's Jean-Baptiste Doumeng and possibly Hong Kong's Li Ka-shing, who owned swathes of the British colony by 1979.

The first confirmed British billionaire (apart from Queen Elizabeth II, whose true personal wealth is difficult to estimate) was also minted in the 1970s as far as we can tell. A New York Times article from 1979 proclaimed landowner Robert Grosvenor, 5th Duke of Westminster (pictured), who died that year, the UK's richest individual with a net worth said to be in excess of $1 billion. The fortune passed to his son Gerald Grosvenor, 6th Duke of Westminster.

The first Forbes 400 List of the richest Americans was published in 1982. The round-up included 15 billionaires, the richest of whom was shipping magnate Daniel Keith Ludwig (pictured) with an estimated net worth of $2 billion, the equivalent of $4.5 billion (£3.5bn) in today's money. Gordon Getty, who inherited a massive fortune from his father J. Paul Getty, snagged position number two. He was said to be worth $1.4 billion, which is $3.2 billion (£2.5bn) in 2019 money.

The other billionaires who featured on the inaugural Forbes 400 List were all estimated to be worth $1 billion. They were America's first female billionaires heiress and hotelier Caroline Rose Hunt and heiress Margaret Hunt Hill (pictured), Lamar Hunt, Nelson Bunker Hunt, William Herbert Hunt, David Packard, David Rockefeller Sr, Forrest Mars Sr, Marvin Davis, Perry Richardson Bass, Philip Anschutz, Patrick McGovern and Sid Bass.

Five years after the introduction of the Forbes 400 List, the magazine launched its famous World Billionaires round-up. Forbes highlighted a total of 140 billionaires in 1987, including 96 outside of the US, which means that between 1982 and 1987 the number of American individuals with 10-figure-plus fortunes grew from 15 to 44.

At this time Japan was nearing the height of an asset price bubble, during which real estate and stock market prices mushroomed. So perhaps unsurprisingly the world's richest person in 1987 was Japanese property investor Yoshiaki Tsutsumi, who was worth $20 billion, the equivalent of $45 billion (£35bn) today. Tsutsumi was followed by fellow countryman Taikichiro Mori, whose fortune that year was estimated at $15 billion, the same as $34 billion (£26bn) in 2019.

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In fact, Japanese billionaires dominated the 1987 top 10, filling six spots, and US billionaires didn't feature in the global round-up. In fact, it would be at least another 10 years before they would be included in the list. Other notable billionaires featured in the first full list included Swedish-born packaging tycoons Hans and Gad Rausing, Canada's Reichmann brothers and notorious Colombian drug lord Pablo Escobar (pictured).

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Forbes rival Fortune released its first global Billionaires List the following year. Due to differing research and calculation methods Fortune included 178 individuals on its list (but this figure includes family members whose total net worth added up to $1 billion or more). The richest person was the Sultan of Brunei (pictured) with a fortune of $25 billion, the equivalent of $54 billion (£42bn) today. He was followed by then King of Saudi Arabia, Fahd bin Abdul Aziz al Saud, with an estimated net worth of $18 billion, $39 billion (£30.3bn) in 2019 money. Fortune stopped producing its annual round-up in 1994.

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The UK's Sunday Times newspaper debuted its list of Britain's richest people in 1989. According to the publication, the UK had seven sterling billionaires compared to the 151 that feature in the 2019 round-up. The richest was Queen Elizabeth II with £5.2 billion which is the equivalent of £12.7 billion ($16.3bn) today and a lot more than the £370 million ($475m) the newspaper has calculated Her Majesty's net worth at this year. Back in 1989, the Queen was followed by Gerald Grosvenor, 6th Duke of Westminster, who was estimated to be worth £3.2 billion.

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As mentioned Yoshiaki Tsutsumi was deemed by Forbes to be the richest individual on the planet in 1987, a title he held onto through to 1990. But in 1991 Tsutsumi was overtaken by Taikichiro Mori, who had a net worth of $18.5 million at the time – that's $34.9 billion (£27.2bn) today. Yoshiaki Tsutsumi was back on top, however, in 1993 and was placed in the number one position the following year to boot. The wealthiest family during this period were Walmart owners the Waltons (pictured).

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The number of dollar billionaires Forbes identified around the world grew from 1987 to 1992: in 1988 the magazine found 191, and in the following year the number increased to 220, which increased to 265 people in 1990. However, in 1991 that number dropped to 260, caused in part by the Gulf War. Nevertheless, numbers recovered in 1992 to hit 275.

But this recovery didn't last long, and the first significant drop in the number of global billionaires came in 1993.  This was no doubt a result of the early 1990s recession, which impacted on the fortunes of a relatively large number of the world's richest people. Forbes counted a total 192 billionaires worldwide that year, down from 275 in 1992.

In 1994 the number was on the rise again, hitting 342, and the total wealth of the world's billionaires began to increase sharply. The following year Forbes identified 366 people with 10-figure-plus fortunes. For the first time since 1987 an American bagged the top spot. Microsoft's Bill Gates was declared the world's richest individual with a net worth of $12.9 billion, the equivalent of $20.6 billion (£16bn) today which is just a fifth of Gates' current net worth. Warren Buffett, who entered the top 10 in 1993, was a close second with $10.7 billion, which would be $17 billion (£13.2bn) today.

While total billionaire wealth was growing in a major way, from $765.4 billion in 1995 to $1.4 trillion in 1999, the number of billionaire individuals globally dropped and plateaued somewhat during the latter half of the 1990s. In 1999 there were 336 in total compared to 422 in 1996. Throughout this time Bill Gates commanded the number one spot.

Bill Gates' fortune soared to $90 billion in 1999 and the number of billionaires spiked in 2000 as the dot-com bubble reached its zenith, with Forbes counting 360. That year, Japan had a record 43 billionaires. Also in 2000, the first female self-made dollar billionaire was minted when domestic mogul Martha Stewart, who had taken her eponymous company public a year earlier, hit the magic figure.

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In 2001 the number reached a record 538. That same year Black Entertainment Television (BET) owner Robert L. Johnson became the first black billionaire. At the time Forbes estimated the net worth of the US TV network proprietor at $1.6 billion. Oprah Winfrey scored a first in 2003 when she made the Forbes list, becoming the first black female billionaire in history.

The dot-com bubble burst in the early 2000s. The crash is reflected in the number of billionaires globally, which fell from 538 in 2001 to 497 the following year and bottomed out at 476 in 2003. Total wealth also dropped over these years, falling from $1.7 trillion in 2001 to $1.5 trillion a year later. In 2003 the figure was even lower at $1.4 trillion. Bill Gates' fortune also fell, from $90 billion in 1999 to $40.7 billion in 2003.

The 2000s saw a considerable increase in the numbers of billionaires from BRICS nations, most notably Russia, India and China. In terms of the countries with the highest number of people with 10-figure-plus fortunes, Russia made the top five in 2003, India was catapulted into the top 10 in 2005, while China, which is now second only to the US, entered in 2008 when it ranked fifth.

Following the dot-com crash, the number of billionaires rose steadily again and total billionaire wealth grew even more dramatically. From 2003 to 2008, the number of people in the world's most exclusive club went from 476 to 1,225, while total wealth skyrocketed from $1.4 trillion in 2003 to $4.4 trillion in 2008. That year, Warren Buffett bypassed Bill Gates to become the richest of them all with a net worth of $62 billion.

Needless to say, the 2008 financial crisis eroded the fortunes of a multitude of billionaires. In 2009 the number of individuals boasting a net worth of 10-figures-plus decreased to 793, down 432 from the previous year, and their total wealth nosedived to $2.4 trillion, a drop of almost half. But there was good news for Gates who returned to the top spot in 2009 after Buffett lost $25 billion as a consequence of a precipitous fall in the price of Berkshire Hathaway stock.

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While less well-off people around the globe have endured years of austerity since the crisis, the billionaires of the world have seen their wealth recover. Total billionaire wealth surpassed the 2008 figure in 2011 when it hit $4.5 trillion, and the following year the number of billionaire individuals overtook 2008 levels when it touched 1,226, according to Forbes.

Bill Gates was pushed off the top spot again in 2010. Mexican telecoms tycoon Carlos Slim Helú (pictured) was número uno that year with a net worth of $53.5 billion. Slim held the premier position until 2014 when Gates reclaimed the spot only to lose it again in 2018 to Amazon billionaire Jeff Bezos, whose wealth smashed through the $100 billion-dollar mark to hit $112 billion. Bezos was also top this year with a fortune of $131 billion (£102bn).

From 2011 to 2018 the total wealth of the world's billionaires increased from $4.5 trillion to a record $9.1 trillion, more than doubling in this time. During the same period the number of billionaires grew from 1,210 to 2,208, another record.

This year Forbes found that the number of billionaires globally had fallen from 2,208 to 2,153, a drop of 55, while total wealth decreased from $9.1 trillion to $8.7 trillion. Possible reasons for the drop include the slowdown in China's economy, but billionaires elsewhere in Asia, as well as in Europe, the Middle East and Africa also took a hit. Bucking the global trend, the number of billionaires in the US rose to a record 630.

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