There's a Kickstarter to bring back Reading Rainbow currently running.

One stat in particular really stands out for me:

Right now, 1 out of every 4 children in America will grow up illiterate.

This is fairly shocking to me, but the Kickstarter itself doesn't provide any sources. I was able to find the claim elsewhere, but again, no sources.

Is it true that 1 in 4 children in America grow up illiterate?