Almost all U.S. adults who drive -- 91 percent -- say they know it is unsafe to use a cellphone while driving, but 60 percent say they do, a survey indicates. The Harris Poll, of 2,163 U.S. adults surveyed online June 13-20 by Harris Interactive, indicates more than one in five drivers with cellphones send or read text messages while driving. However, the percentage of drivers with cellphones who use them while driving dropped over the last two years, from 72 percent in 2009 to 60 percent today, while the numbers who text while driving dropped from 27 percent to 22 percent. However, recent research shows both hand-held and hands-free cellphones are almost equally dangerous because they are equally likely to distract drivers, but 77 percent say hands-free phones are safer, the poll says. The survey also says: -- 57 percent of drivers rate themselves as better-than-average drivers, only 1 percent rate themselves as worse than average. Sixty-six percent of men say they are better-than-average drivers, compared with 48 percent of women. -- 49 percent of drivers with cellphones under age 35 send or read text messages while driving compared with 24 percent of Gen X ages 35-46, 11 percent of baby boomers ages 47-65 and less than 1 percent of those ages 65 and older.