Predictable observations have greeted the latest billionaire rankings from Forbes: the swelling ranks of the developing-world rich; the relative few 747-owning Japanese and Germans; the rise of social networking wonderkids and the absence of embarrassing billionaires the likes of which are on the run across the Middle East these days. But for most, the whole exercise remains strangely academic.

That is because very large numbers tend to lose their meaning. The average net worth of the world’s 1,210 billionaires, at $3.7bn – up a couple of hundred million dollars versus 2010 – is more or less incomprehensible to, say, an American with a median net worth at the last census of $120,000. Ask the average Joe to imagine a brand new 160ft Millennium Casino Royal superyacht and he will stare blankly. Only revealing that the boat costs almost $60,000 to fill up with diesel, for example, can give its stratospheric price tag meaning.

And that is just one yacht. How on earth to comprehend $3.7bn in net assets? Put it another way. Pretend the UK’s Bruno Schroder and his family – 297th on the list with exactly that amount, according to Forbes – are sick of the banker bashing and desire as risk-free a life as investing allows. Putting their fortune into 30-year US Treasuries and taxing the income at 40 per cent would give them a yearly allowance of $100m. That’s $270,000 every day. Even with only a 20th the net wealth of Carlos Slim, the richest person on the list, the Schroders would find that hard to spend.