From New York Post:

Three-quarters of Americans have at some point in their lives thought they knew of a child being abused - but only 12 percent of them actually decided to report it to authorities, a first of-its-kind-survey shows.

A disturbing 78 percent said they suspected seeing abuse, but 33 percent kept silent because they didn't want to get involved, according to the national survey released by Safe Horison, a Manhattan child advocacy group.

Read rest of the story here:
http://www.nypost.com/seven/09262008/news/nationalnews/kid_abuse_poll_shock_130771.htm