How many boomers are there?

So, the Census Bureau today reported that there will be 298 million people in America come New Year's Day. But how many will be boomers, who start turning 60 on Jan. 1. I've seen all sorts of figures, from 76 million to, today in USA Today, 79 million. The bureau says there are 78.2 million boomers, as of July 1, 2005.