Nudity on prime time U.S. broadcast TV jumped fourfold in a year, a conservative advocacy group said, calling on Congress to insist regulators do their job. Blurred nudity on TV was 407 percent greater in the 2011-2012 season than in the season before, with 76 incidents of full nudity on 37 shows, compared with 15 incidents on 14 shows the year before, the Parents Television Council said in a statement Monday. This represents a 407 percent increase, the group said. Nearly 70 percent of the pixilated scenes cited as including nudity aired before 9 p.m. \"and as early as 7 p.m.,\" the group said. By contrast, half the full nudity scenes monitored by the group the year before aired after 9 p.m., the group said. Of the 76 cited incidents, five were on shows containing an \"S\" TV content sub-rating used with TV Parental Guidelines\' TV-PG, TV-14 and TV-MA ratings to indicate instances of sexual content, the group said. \"PTC research has found a staggering increase in the frequency and explicitness of pixilated nudity on the broadcast networks during prime time hours,\" group President Timothy F. Winter said in a letter to members of House Energy and Commerce Committee and the Senate Commerce Committee, both of which oversee communications regulation. \"In 2006, Congress passed the Broadcast Decency Enforcement Act in response to growing outrage from the American people over the broadcast networks\' abuse of the publicly owned broadcast airwaves,\" the letter said of the act that increases fines and penalties for violating prohibitions against broadcasting obscene, indecent or profane language. \"Yet since that time, we have seen a concerted effort on the part of the networks to constantly push the outer limit of what may be considered appropriate for the broadcast medium,\" it said. The letter called on lawmakers to urge the regulatory Federal Communications Commission to clear a \"backlog of 1.6 million unadjudicated indecency complaints\" and to empower the FCC \"to ensure enforcement actions are meaningful and appropriate.\" The FCC did not immediately respond to a phone inquiry asking about the alleged backlog of indecency complaints. The PTC said it reach its conclusions after studying TV programs from Sept. 1, 2011, to May 31. Its analysis excludes \"animated nudity or suggested full nudity and only includes scenes in which individuals are completely unclothed and only the sexual organs are blurred from the viewer,\" it said. The analysis includes TV specials but excludes regular news and sports.