The United States surpassed Europe and Japan in terms of annual output per worker for the first substantial period since World War II, according to a United Nations study published on Monday. The survey of global labor market trends from the Geneva-based International Labor Organization showed that the productivity gap between the U.S. and the rest of the world widened in 2002 due to Americans working longer hours than Europeans. Americans clocked up an average of 1,825 working hours last year, compared with 1,300 to 1,800 hours in leading European economies. Output per worker in the United States grew 2.8 percent in 2002 from the previous year, more than double the 1.2 percent growth rate across the European Union. According to the study, three European countries are doing better than the U.S. in terms of output per hour -- Belgium, Norway and France.