If you’re graduating from college this year, count yourself lucky.

Just 56 percent of college students earn four-year degrees within six years, according to a 2011 Harvard Graduate School of Education study. Among the 18 developed countries in the OECD, the U.S. was dead last for the percentage of students who completed college once they started it ― even behind Slovakia.

PHOTO GALLERY: The 11 Universities with the Worst Graduation Rates

College dropouts tend to be male, and give reasons such as cost, not feeling prepared, and not being able to juggle family, school and jobs, according to the Harvard study. An American Institutes for Research report last year estimated that college dropouts cost the nation $4.5 billion in lost earnings and taxes.

A number of four-year public universities, funded in part by taxpayer dollars, have graduation rates that are just as bad ― or worse ― as their for-profit counterparts.

One force behind these disappointing statistics are America’s for-profit schools, which have garnered plenty of media attention for being “dropout factories” that send students out into the workforce with major debt and few skills. But there are a number of four-year public universities, funded in part by taxpayer dollars, which have graduation rates that are just as bad ― or worse ― as their for-profit counterparts.

RELATED: Why America’s College Students Don’t Graduate

Calculating college graduation rates isn’t an exact science – the data look at the number of incoming Bachelor’s degree-seeking students who graduate within six years, and dropouts include students who transfer to other schools. Still, the high number of dropouts is concerning. The following list is from calculations by the Chronicle of Higher Education for the 2010 year (the latest data available). We included only four-year accredited universities, and didn’t include schools with a high percentage of part-time students.

Click here to see the 11 universities with the worst graduation rates.