Although American children still spend part of their days reading, they are spending less time doing it for pleasure than decades ago, with significant gaps in proficiency, according to a report released on Monday. The San Francisco-based nonprofit Common Sense Media, which focuses on the effects of media and technology on children, published the report, which brings together information from several national studies and databases. “It raises an alarm,” said Vicky Rideout, the lead author of the report. “We’re witnessing a really large drop in reading among teenagers and the pace of that drop is getting faster and faster.” The report found that the percentage of nine-year-old children reading for pleasure once or more per week had dropped from 81 percent in 1984 to 76 percent in 2013, based on government studies. There were even larger decreases among older children. A large portion rarely read for pleasure. About a third of 13-year-olds and almost half of 17-year-olds reported in one study that they read for pleasure less than twice a year. Of those who read or are read to, children tend to spend on average between 30 minutes and an hour daily with that activity, the report found. Older children and teenagers tend to read for pleasure for an equally long time each day. Rideout cautioned that there may be difference in how people encounter text and the included studies may not take into account stories read online or on social media. The report also found that many young children are struggling with literacy. Only about one-third of fourth grade students are “proficient” in reading and another one-third scored below “basic” reading skills. Despite the large percentage of children with below-basic reading skills, reading scores among young children have improved since the 1970s, according to one test that measures reading ability. The reading scores among 17-year-olds, however, remained relatively unchanged since the 1970s. About 46 percent of white children are considered “proficient” in reading, compared with 18 percent of black children and 20 percent of Hispanic kids. Those gaps remained relatively unchanged over the past 20 years, according to the report. “To go 20 years with no progress in that area is shameful,” Rideout said. The report highlights some behaviors that have been tied to children being more frequent readers. Those behaviors include parents setting aside time to read with their children and parents reading themselves to model good behavior.