Much has been made lately of how American work culture can make overwork into a badge of honor, instead of a pathology that ends up diminishing productivity and quality.

Although Americans put in more hours than most other wealthy nations, a few countries work even more, including Korea and Mexico. But at least compared with wealthy European nations, Americans are far more likely to work on weekends or in the dead of night, what the authors of a new NBER working paper call “strange work” (work performed between 10pm and 6am).

Using time-use survey data and work diaries, the researchers found that Americans’ work on the weekend exceeds that of the UK, Germany, France, the Netherlands, and Spain. On a typical day of a week, a quarter of American workers burned the midnight oil.

Here is how the six countries in the study (which did not look at countries outside of Europe) stack up when it comes to working at strange hours. The percentages note the likelihood of a person working on a Saturday or Sunday, or between 10pm and 6am, during a given week. (Note that the data does not always come from the same year, and that night work data is unavailable for Spain.):

These strange work hours probably happen because Americans work so much and lack the enforced vacations and limitations on overtime that exist in some European countries. Nearly twice as many US workers work 45+ hour weeks than in Germany, and more than twice as many do so than workers in France, the Netherlands, and Spain. As the work week grows longer, weekend and “strange” work becomes much more likely.

This stands to reason: Someone moving from a comparatively standard week of 35 to 44 hours to a 55- to 64-hour week is almost twice as likely to let that work bleed into weekends and nights, according to the study.

In recent decades, work hours have actually gone down around the world. Many countries adopted controls or limitations on the work day, and technology helped reduce hours. Comparing annual work hours in 1979 and 2012, America’s overall work hours declined slightly, but saw less of a drop than any country except for Sweden, where hours increased:

So what would happen to the US if it adopted similar controls? According to the study, if the country adopted the French distribution of work hours, night and weekend work would drop substantially, but would still remain well above that of continental Europe.

Given the potential health and personal impacts of overwork, Americans should perhaps consider some kind of intervention.