There has been some press about the two reports in the March 4th issue of the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report.
In the first report, 35.3% reported having <7 hours of sleep on average during a 24-hour period. 37.9% reported unintentionally falling asleep during the day at least one day in the prior 30 days, and 4.7% reported nodding off or falling asleep while driving in the preceding 30 days.
In the second report, 37.1% of adults reported regularly sleeping less than seven hours per night. Perceived sleep-related difficulties were more likely among individuals reporting <7 hours of sleep as compared with those reporting 7-9 hours of sleep; the most prevalent was an inability to concentrate on doing things (23.2 percent).
As others have stated, both of these reports suggest that more than one-third of American adults are not getting enough sleep. It would be interesting to know if the the same 35.3% who get <7 hours of sleep were among the same 37.9% who felt sleepy during the day. As sleep needs vary, some people can get by on less than 7 hours. Also, some still feel sleepy with more than 7 hours if their sleep quality is reduced by a medical or sleep disorder.