Students scored an average of 288 out of 500 points in reading comprehension, two points better than in 2005 level but four points below the 1992 average of 292, the 2009 National Assessment of Educational Progress said Thursday.
Thirty-eight percent of 12th graders scored at or above "proficient" in reading and 26 percent scored that well in math, said the report, known as the Nation's Report Card.
"Today's report suggests that high school seniors' achievement in reading and math isn't rising fast enough to prepare them to succeed in college and careers," U.S. Education Secretary Arne Duncan said in a statement.
White and Asian and Pacific Islander students made gains in reading since 2005 but no racial, ethnic or gender group has shown significant changes in scores since 1992. Asian students scored an average of 298 points in reading in 2009, higher than any other group.
Students attending suburban schools scored higher on average than those attending schools elsewhere.
West Virginia showed the lowest overall scores for math and reading among 11 pilot states that volunteered in a pilot program to show results by state -- although black students in West Virginia scored higher than black students in any other state.
Reading scores in seven pilot states -- Connecticut, Idaho, Illinois, Massachusetts, New Hampshire and South Dakota -- were higher than the national average.