Every year, the estimated number of U.S. households owning TV sets goes up. Until now.

According to Nielsen Media Research’s annual “Television Audience” report that was released this week, the number of households with a TV set will decline for the first time in the company’s survey history (which extends back to 1970). The rising trend of TV ownership has been leveling off in recent years, and now the number has dropped from 115.9 million homes in 2011 to an estimated 114.7 million in 2012. As TV Barn pointed out, that’s a 1 percent decline despite the number of households rising.

TV ownership among the key adult 18-49 demo also declined, and even steeper (down 2.7 percent — a downtrend that started to a slight degree in 2010 and then accelerated this year). Plus, the percentage of homes without a TV is at the highest level since 1975 (3 percent, up from 1 percent the previous year).