DES MOINES Iowa

Iowa high school graduates' average ACT scores increased slightly this year and remain among the highest nationally.

The average composite score for Iowa students who graduated this year was 22.3 1.1 points higher than the national average and tied for ninth best nationwide. Among the 26 states that had at least half their graduates taking the test, Iowa tied for second with Wisconsin. Minnesota was first with a 22.5 average score.

The results were released Wednesday by ACT, the Iowa City-based nonprofit that owns the college entrance exam. Scores range from 1 to 36 and cover math, science, English and reading. Colleges and universities nationwide use them to help determine admissions, scholarships and academic advising.

Iowa's score increased 0.2 percentage points from a year ago, when it ranked third nationally. Sixty-six percent of the state's graduating seniors took the exam.

"The educational improvements we've put in place are paying off," said Linda Nelson, president of the Iowa State Education Association. "But we're not content to rest on our laurels. Iowa's teachers pledge to continue focusing on the things that really make a difference for student achievement."

Nationally, the high school class of 2007 posted a modest increase, extending the test's upward scoring trend and showing improved levels of preparation for college.

Still, the results highlight the persistent gap between the preparation levels of high school graduates and the skills they need to do well in college. Only 23 percent of test-takers met a benchmark score that indicates readiness in a range of introductory, core college courses.

The national average ACT composite score rose from 21.1 last year to 21.2, extending its recent pattern of slight but noticeable increases.

The ACT says one-year trends are not necessarily meaningful, but that the average scoring increase of 0.4 points since 2003 is significant, considering 1.3 million of this year's high school graduates took the test.