Yearly work hours are accumulated from survey data and holidays and absence days subtracted. Thus the actually worked hours per year are obtained. Then those are divided by the number of weeks to get the actually worked hours per week (see OECD-Employment Outlook 2007). Multiplying these again by the employment participation ratio produces an approximation of a measure of “Hours actually worked per week, per person at working age”, which we use as an indicator of the total volume of work of a nation.
Here is a close upp view of the four countries who work the most: