Paris: Boosted by record-breaking New York sales of a Picasso painting and a Giacometti sculpture, the United States has become the world’s leader in public art auctions, unseating China, says a report by Artprice. The US art auction market grew by 20 per cent in the first six months of the year, with sales totalling $ 2.8 billion (2.5 billion euros), a billion more than China with sales worth $ 1.9 billion.