Higher earning workers in the US work more hours than lower earning workers.
"Between 1979 and 2002, the frequency of long work hours increased by 14.4 percentage points among the top quintile of wage earners, but fell by 6.7 percentage points in the lowest quintile."
There are insinuations in this thread that the reason Americans work more hours is because the working poor have to work long hours to make ends meet. However, "There was no increase at all in work hours among high-school dropouts," from 1979 to 2002.
Americans working long hours is increasingly a higher income phenomenon. Which means those workers have more disposable income they could trade for shorter hours if they chose to.