Whatever the economic uncertainties of the past couple of years, stoked by US-China trade tariffs and Brexit, the art market has proved itself able to float serenely above such petty concerns. The figures for 2019 aren’t yet available, but 2018 saw the global market to be thoroughly in the pink with sales of $67.4 billion, its second-highest level in 10 years. To put that sum into perspective, it is the equal of the GDP of Bulgaria and greater than that of such countries as Croatia, Uruguay, Bahrain and Iceland.

Most notable, however, is not the figure itself but that works of art selling for more than $1 million accounted for fully 61 per cent of total sales value yet represented just one per cent of lots sold. What’s more, post-war and contemporary works (by artists born after 1910) accounted for half the fine art auction market’s value.

Should you be selling, therefore, it is worth checking your attic for a post-1945 painting; that’s what collectors want at the moment and that’s what they are willing to spend epic sums on. It is a trend confirmed by the 10 most expensive paintings sold at auction in 2019. Together they totalled a whopping $660,375,350 and only two of them were painted prior to 1952. It takes a slight mental adjustment to realise that today’s top collectors are not going for works by art’s most hallowed Old Masters but by artists who could be their own contemporaries.

Put another way, the most expensive post-war work sold last year was Jeff Koons’s “inflatable” metal Rabbit — a shiny, oversized gewgaw — which fetched just over $91 million; the most expensive Old Master, on the other hand, was a panel by Cimabue (c1240-1302), one of Renaissance art’s founding fathers, found hanging in a provincial French kitchen and sold for $21.5 million.

Of the 13 most expensive paintings ever sold, six are by Americans.

The koons wasn’t even last year’s most expensive work; that honour went to Monet, whose Meules, a vivid-hued haystack painting from 1890, made a little over $110.7 million. In doing so it became the most expensive Impressionist painting ever sold at auction and made the seller’s purchase in 1986 look a particularly canny piece of business: then it fetched $2.5 million and so has been appreciating at $3.25 million every year since.

The fourth-best performer in 2019 was another Impressionist-circle work, Paul Cézanne’s still life of a pitcher and fruit from 1888–90, which made $59.3 million. Both men are consistently high performers: in 2018 a Monet waterlily painting went for $84.7 million while Cézanne is one of only a handful of artists to have two paintings that have sold for more than $100 million.

Last year’s most expensive list also underlines other market proofs: all of the artists were male, five were American, and nine of the paintings were sold in New York. America indisputably rules the post-war art world. Indeed, even the subject of the tenth most expensive painting on the list, a Hockney portrait that made $49.5 million, is an American — the influential curator Henry Geldzahler.

This Americanisation shows little sign of abating. Of the 13 most expensive paintings ever sold, six are by Americans. No fewer than 300 works by Andy Warhol (he turned out some 10,000) have made more than $2.7 million, the most expensive fetching $105.5 million. Meanwhile, Jasper Johns’s top price is $110 million and even an artist as recondite as Barnett Newman has commanded $84 million.

In most instances the list merely confirmed existing reputations — Robert Rauschenberg ($88.8 million), Picasso ($54.9 million), Warhol ($53 million), Francis Bacon ($50.3 million), Rothko ($50 million). The real surprise was the appearance of Ed Ruscha’s Hurting the Word Radio #2 from 1964, a breezy bit of word art showing the word “Radio” being tortured by a pair of woodworking clamps, which made a barely believable $52.5 million. Ruscha is hardly an unknown quantity, but the price added a full $20 million to his previous auction record. More curiously there are two other versions of the work — both in museums — and the picture itself is banal.

Ruscha made his name in the 1970s in part from word art which he helped make into a distinctive offshoot of American Pop Art. Hurting the Word is not, however, one of the earliest or one of the most effective (his phrase pictures have more ooompf, relatively at least). Rather like a Banksy, it has an instant graphic effect but offers little more on repeated viewings. Christie’s chairman of post-war and contemporary art Alex Rotter rather gave the game away: “We wanted to prove we could sell a painting over $50 million this season.” Forget about quality, with aggressive marketing any painting would do, it seems.

What the anonymous bidder got for his or her money is, however, a recognisable work by a recognisable name that will add a touch of vivacity, albeit a garish one, to their walls. It remains debatable whether Ruscha, now 82, fully deserves his place in the company he finds himself keeping — he is, when all is said and done, a very limited artist. What he most certainly is not, whatever the market says, is an artist of more than double the skill, profundity or importance of Cimabue.