Aug. 16 (Bloomberg) -- Almost four-fifths of U.S. high school graduates failed to pass this year's standard examinations designed to show their readiness for college, test designer ACT Inc. reported.

Scores on the four-part ACT test, taken this year by more than 1.2 million U.S. students, ranged from only 27 percent passing in biology to 69 percent in English, the company reported. A total of 21 percent met the benchmark in all four subject areas, including algebra and social science, it said.

The nationwide average total score on the ACT test rose the fastest in 20 years, yet the overall performance remains unacceptable, U.S. Education Secretary Margaret Spellings said.

``The ACT findings clearly point to the need for high schools to require a rigorous, four-year core curriculum and to offer advanced placement classes so that our graduates are prepared to compete and succeed in both college and the workforce,'' Spellings said in a statement.

The ACT tests, based on curriculum surveys of high school and college instructors, serve as a competitor to the SAT test administered by the New York-based College Board. ACT's benchmark for passing is designed to indicate a 50 percent chance of obtaining a grade of ``B'' or higher in the college-level course.

More than 40 percent of U.S. high school graduates took the ACT tests this year, said Richard Ferguson, chief executive of the Iowa City, Iowa-based company. Yet the low pass rate suggests that many college students will ``struggle or need some remediation along the way,'' Ferguson said.

``We have a lot of work ahead of us to ensure that all students graduate from high school with the skills they need to succeed at the next level of education,'' he said in a briefing on the results.

To contact the reporter on this story: Paul Basken in Washington at pbasken@bloomberg.net

Last Updated: August 16, 2006 00:02 EDT