Graduates listen to President Obama as he delivers the Commencement Address at Barnard College's graduation ceremony in New York on May 14, 2012. (Timothy A. Clary/AFP/Getty Images)

Women are attending college at higher rates than men, graduating in greater numbers and earning higher grades. Yet one year after graduation, women were making only 82 percent of what their male colleagues were paid, according to a report by the American Association of University Women set to be released Wednesday.

Nearly every occupation has long paid men more than women, despite laws aimed at narrowing and dissolving the differences. Often the gap is attributed to men picking careers with higher salaries, women slowing their careers after having children and differences in work experience. The AAUW researchers decided to look at workers when they are most similar — freshly done with their undergraduate studies, lacking vast experience and unlikely to have spouses or children.

They focused on those who graduated during the 2007-08 school year, zeroed in on full-time workers and studied what they earned in 2009, one year after graduation. The women made only 82 percent of what the men were paid, with the average woman making $35,296 while men were paid an average of $42,918.

The report relied on data from an Education Department survey of about 15,000 college graduates via Web or telephone surveys.

Even when men and women had the same majors, there were often gaps in pay. The researchers found that female business majors earned an average of slightly more than $38,000, while men earned just over $45,000. In engineering, technology, computer science and social sciences fields, researchers found that women made between 77 percent and 88 percent of what their male colleagues were paid. (The health-care and education fields were credited for paying men and women about the same.)

But the overall gap — the 18-percentage-point disparity — could be explained by career choices; men are more likely to enter high-paying fields such as engineering and computer science. The researchers controlled for that, along with other variables, but an “unexplained” 6.6-percentage-point gap remained.

“This pay gap is not merely the result of women’s choices,” researchers Christianne Corbett and Catherine Hill wrote in their report, “Graduating to a Pay Gap.” “Lower earnings have an immediate effect after college, setting into motion a chain of disparities that will follow women throughout their careers.”

One of those disparities: If women earn less, they will have a harder time repaying their student loans, a “significant and growing problem,” the researchers wrote. For the Class of 2008, the average amount of student loan debt was about $20,000, an amount that didn’t vary much between the genders, although women were more likely than men to have taken out loans.

The researchers put forward suggestions for reducing the pay gap, including encouraging women to pursue careers in higher-paying fields and to negotiate higher pay.

“A problem as long-standing and widespread as the pay gap, however, cannot be solved by the actions of individual women alone,” the researchers wrote. “Employers and the government have important roles to play. The pay gap has been part of the workplace so long that it has become simply normal.”