Ouch! "The more I find out, the less that I know". This site gives extensive statistics, broken out nationally and by year from 2000-2010. According to their numbers, for 2010, Korea had the largest numbers of hours worked, with the U.S. 12th on the list and Japan 15th. It looks like the shifts across this decade are considerable (10%-20%, for many of the nations). Looking at a bunch of sites, there seems to be considerable differences in reported numbers as well - the definitions of what hours they include and who they include may differ...