Amid a national push to reduce screen time in schools, elementary and middle school students report less of their free time is spent reading. The share of 13-year-olds who read for fun has declined by nearly half since 2012, according to survey data published Wednesday by the Education Department’s National Center for Education Statistics . The share of 9-year-olds — the other age group studied — who read for fun has declined 16 percentage points in the past 13 years. Students’ reading for pleasure generally correlates with higher reading scores on standardized tests, according to the report, with more dramatic gains for teens who say they read every day, compared with their peers who don’t. The questionnaire is part of the National Center for Education Statistics’ nationwide math and reading testing for 9- and 13-year-olds. The most recent report includes data from more than 30,000 students, and the test itself has been conducted since the 1970s.…