More than half of the people who are 100 years old or older didn’t think they’d live that long, according to a survey UnitedHealthcare released this month that looked at both centenarians and 65-year-old baby boomers.

The survey found 24 percent of current centenarians expected they would live to see their 100th birthday while 28 percent of baby boomers expect that they will live to be centenarians.

It also found baby boomers are more likely than centenarians to read a newspaper or a book (85 percent vs. 72 percent), cook a meal for themselves or others (83 percent vs. 48 percent), work at a hobby (61 percent vs. 38 percent) and play with their grandchildren or great grandchildren (42 percent vs. 22 percent).

Centenarians do have baby boomers beat in one area, though. The survey found that 79 percent of people who lived past their 100th birthday are able to get eight hours of sleep each night. The same is true for only 61 percent of boomers.