One of the many things economic development buys is longer life. In countries with per-capita GDPs of $1,000 to 2,000 per year, like Haiti, people can expect to die when they’re about 60, but when that figure rises to $40,000 per year, like in Japan, people live until they’re about 80 on average.

This is, however, not the case among poor Americans, who are dying younger in greater numbers, or in so-called “overachiever” countries like Costa Rica, where people live about as long as Norwegians even though they’re about as poor as Iraqis.

Now, a surprising new study shows that in terms of mortality, it’s actually better to be poor in Costa Rica than poor in the U.S.

According to research published by Luis Rosero-Bixbya from the Universidad de Costa Rica and William H. Dow from the University of California, Berkeley, in the Proceedings of the National Academy of Sciences, the richest Americans do indeed live longer than the richest Costa Ricans—something you’d expect when comparing a global economic powerhouse to a tiny Latin American country. But Costa Ricans in the lowest fourth of the country’s income spectrum have a significantly lower age-adjusted mortality rate than their counterparts in the United States.