Need to figure out if you have enough gasoline to make it to the next station? You can ask a college graduate to do the calculations -- well, maybe.

A report released Thursday found that 20 percent of graduates of four-year programs and 30 percent of those earning two-year degrees lack the quantitative skills to do such a calculation. The report found that the mathematical skills of today's graduates aren't any worse than those of previous generations, and that in other forms of literacy, today's graduates are doing better. But the report will not be welcome news to college presidents, many of whom are still answering questions about a study last month that found declining levels of literacy among college graduates.

The new report was issued by the American Institutes of Research, which conducted the study of students about to graduate from 80 randomly selected colleges -- with a mix of two- and four-year, public and private institutions. The work was supported by the Pew Charitable Trusts.

The students who can't calculate whether you have enough gasoline to make it to the next stop have "basic" quantitative skills, the report says. That means, for example, that they could add the price of a sandwich and the price of a salad on a menu. Only about 1 percent of graduates (the same at four-year and two-year institutions) lacked even that level of computational skill.

The study also looked at levels of literacy with regard to prose and documents -- and it was in those areas that college graduates didn't have such limitations. The study's authors also noted that there were not significant gender gaps in scores on these various forms of literacy -- a notable change from past studies in which women lagged.

Racial and ethnic gaps are visible in the scores, with white graduates outperforming those of all other groups, across literacy type and institution.

Other findings of the study:

• Graduates of four-year colleges generally have higher levels of literacy than do graduates of two-year colleges.
• There were not significant differences in the skill levels found among graduates of public vs. private colleges, part-time vs. full-time students, or two-year graduates of technical vs. two-year graduates of academic programs.
• Most majors do not seem to have significantly different levels of literacy, but there are positive impacts on literacy for those who take courses in analytic thinking and among those who plan to eventually go to a professional school.
• Family wealth is not a major predictor of students' literacy levels, but there is a strong correlation based on the level of education of graduates' parents. Those whose parents graduated from college have significantly higher levels of literacy than do those whose parents did not.