Courtesy of Business Insider and Vizual Statistixs is a map displaying which members of the Organisation for Economic Co-Operation and Development (OECD), a club of 34 mostly-developed nations, works the hardest. This is determined by combining the average number of hours worked annually by each person, the average retirement age, and life expectancy. (See a larger version here.)
So Mexico, South Korea, and Chile are by far the hardest working countries, while France, Germany, and Luxembourg are the least hard-working. The United States is slightly harder working than the median, but definitely more so than its Anglophone cousins and most of Western Europe. Also note that Greece is relatively hardworking by European standards, despite being widely denounced as a nation of laggards following its economic collapse (which certainly had to do with a lot more than average hours worked).
To be sure, this formula that does not take into account other details, such as how hard employees work per hour, but it is nonetheless something to go by. Also, I am not sure if working long hours and having less retirement time is, in and of itself, a good thing. Productivity per hour, the quality of the work, and for more importantly the quality of life in general, should count for a lot more.