Some 22 states now require students to pass so-called "high stakes" tests to graduate from high school. More states are expected to begin requiring the tests, and those that have them reportedly plan to make them tougher.

• No one has an accurate count of how many students have failed the tests nationally, but experts believe the number is easily into the tens of thousands -- possibly many more -- since the tests were introduced in the 1980s.

• In Ohio, about 10,000 students have flunked the tests in the past four years.

• Nearly 3,000 students failed in Florida this year.

The failure rates should not be surprising, education critics contend. More than 10 million Americans since 1983 have reached the 12th grade not having learned to read at a basic level, according to a new report from The Center for Education Reform. More than 20 million have reached their senior year unable to do basic math, and almost 25 million didn't know the basics of U.S. history.