Physicians have reduced their average weekly hours from 55 in 1996 to 51 in 2008, after two decades of remaining mostly unchanged, according to a study published in the Journal of the American Medical Association, the AP/Chicago Tribune reports. The decrease in hours equates to losing about 36,000 physicians over 10 years.

The report showed that the decline was linked to reduced fees paid to physicians. Between 1995 and 2006, fees paid to physicians declined by 25% after inflation. The study found that physicians who worked in cities where fees are higher on average worked longer hours compared with doctors who worked in cities with lower average fees. The results also showed several other factors contributed to the decline.

According to the researchers, if the trend toward lower hours continues, expanding and maintaining the current physician supply may be difficult. However, they note that larger medical school classes and an increase in immigration of international medical graduates could alleviate the problem.