40% of Americans Have Been Born Since 1989?

The "Talk of the Town" section of the latest New Yorker starts out with a bit about people suffering from Clinton-Bush fatigue after nearly twenty years of people of those families in the White House. Hendrik Hertzberg's piece quotes an AP story saying "Forty per cent of Americans have never lived when there a Bush or Clinton in the White House."

Is this true? Perhaps if you count Bush as Reagan's VP. But even then, 40% of Americans are age 27 or younger? I don't know about that.

I suppose I could go do some research on the matter or something, but do I like a damn scholar?