TIANJIN - About 80 percent of China's primary and middle school students aren't getting enough sleep, according to a report released on Monday in North China's Tianjin Municipality.

The average sleeping time for China's elementary and middle school students is less than eight hours, even on weekends, according to the report released by the China Youth and Children Research Center (CYCRC).

The report was based on three surveys of more than 5,000 elementary and middle school students in ten provincial-level regions. The surveys were conducted in 1999, 2005 and 2010.

"Heavy workloads, poor study habits and long commute times have all contributed to the sleep shortage," said Deng Xiquan, a scholar who works with the CYCRC.

According to the CYCRC, elementary and middle school students should get ten and nine hours of sleep each day, respectively.