By Ian Simpson
WASHINGTON (Reuters) - U.S. 12th graders' average mathematics score in 2015 was lower than two years before, and reading performance had stagnated, the Education Department said in releasing the "nation's report card" on Wednesday.
The data also showed a higher percentage of high school seniors failed to reach basic levels in the two subjects, while the lowest-performing students had done worse.
Education Secretary John King Jr said teachers had been revamping classroom practices to adapt to new and higher standards over the seven years of the Obama administration.
"We know the results of those changes will not be seen overnight, so we need to be patient - but not passive - in continuing to pursue the goal of preparing all students for success after high school," King said in a statement.
The reading score fell to 287 in 2015 from 288 two years before, and is down five points since 1992, the first assessment year for reading, according to the report, the National Assessment of Educational Progress (NEAP).
The mathematics score fell to 152 last year from 153 in 2013, a statistically significant drop, it said. The 2015 math mark was largely unchanged from that posted 10 years before, when the current benchmark began.
Students performing at or above proficiency fell to 25 percent in math and to 37 percent in reading. Both were down 1 point from 2013.
The percentage who fell below the basic level of performance last year rose to 38 percent in mathematics and to 28 percent in reading, both rises of 3 points.
The score of students in the 10 percentile, or where nine out of 10 students perform better, fell sharply, with a six-point drop in reading and four points in mathematics.
The NEAP test is often called the "nation's report card" because it is the only measure of student achievement given periodically to students across the United States. It is given to students in fourth, eighth and 12th grades.
The math assessment measures students’ skills and ability to apply knowledge to problem solving. The reading gauge asks students to answer questions based on materials they have read.
About 13,200 students took the math test, and almost 19,000 were tested for reading, the Education Department said.
(Reporting by Ian Simpson; Editing by David Gregorio)