What do the world's billionaires have in common?

A certain globe-conquering Swedish pop band once sung that "it must be funny, in a rich man's world."

With the 62 richest people in the world owning half of its accumulated wealth, they are laughing all the way to the bank.

The 1826 lucky billionaires living the high life as of the end of 2015 have accrued a staggering net worth of $US7.05 trillion (that's $9,900,000,000,000) between them, and that's up over a trillion on the previous year.

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American magazine Forbes keeps tabs on this insanely wealthy bunch, releasing an annual round-up in March. While we wait for the latest tally (you can track real-time results on forbes.com) British financial services comparison website gocompare.com has drilled down into the detail of the top 100, dubbed the Billionaires' League, giving a fascinating insight into their makeup.

Battle of the riches

While it's true that the two richest people in Australia in 2015 were both female – US citizen and heiress Blair Parry-Ockenden ($8.5 billion, ranked 156th) and mining magnate Gina Rinehart ($12.3bn, 94th, but has subsequently slipped to second spot, just outside the top 100) – the Billionaires League resolutely remains a boys' club.

As of the end of last year, only 12 women made it into the top 100 worldwide, with the richest being Wal-Mart co-owner Christy Walton ($41.7 billion, 8th place), just ahead of L'Oreal matriarch Liliane Bettencourt ($40.1 billion, 10th).

However, their ranks have swollen by one-third since the GFC, up from nine in 2008, and quadrupled since the start of this century, so at least the curve would appear to be heading northwards, even if breaking the glass ceiling to gender parity is still a long way off.

Age of empires

The average age of the top 100 billionaires is 60 years, which happens to be the exact birthday celebrated last year by the world's richest man, Microsoft guru Bill Gates ($79.2 billion, ranked number one). That's up from a spritely 47 years back in 1996, which suggests the world's richest are living longer and holding onto their money, too.

43 billionaires hung around in the top 100 between 2006-2015, with a third of those dropping out joining the grim reaper.

That's not to say there aren't a few young guns snapping at their heels. Facebook founder Mark Zuckerberg is the richest, youngest billionaire with an estimated $33.4 billion fortune (16th) at a comparatively fresh-faced 31, though at only 24, Snapchat co-founder Evan Spiegel, 24, is on the up ($2.1 billion, 327th).

Origin of the species

Of the top 100 billionaires, almost 60 per cent accrued the goods themselves, rather than having their wealth dished up on a silver plate by the parents. The land of the brave accounts for 40 per cent of the Billionaires League, with seven Americans in the top 10, with the likes of canny investor Warren Buffet ($72.7 billion, 3rd) and Oracle founder Larry Ellison ($43.9 billion, 5th) keeping Gates and Walton company.

What GFC? Though it's true the Billionaires' League saw their net worth plunge by almost 40 per cent in the year following the 2008 financial meltdown, they've recovered remarkably well since, replenishing their coffers by 123 per cent to rake in over $1,600 billion between them last year.

If you're the sort who believes their destiny is written in the stars, you might be interested to know that the greatest proportion of the top 100 are Aquarians, at 12.5 per cent.

It's also worth noting that an education won't necessarily buy you good fortune, as just under quarter of the top 100 dropped out of school without any qualifications.

Check out more billionaire comparisons here.