As many as 20,000 children endured sexual abuse at Dutch Catholic institutions over the past 65 years, and church officials failed to adequately address it or help the victims, according to a long-awaited investigative report. Based on a survey of 34,000 people, the report estimated that 1 in 10 Dutch children suffered some form of sexual abuse - a figure that rose to 1 in 5 among children who spent part of their youth in an institution such as a boarding school or children's home, whether Catholic or not. Sexual abuse of minors," it said bluntly, "occurs widely in Dutch society." The abuse ranged from "unwanted sexual advances" to rape, and abusers numbered in the hundreds and included priests, brothers and lay people who worked in religious orders and congregations. The number of victims who suffered abuse in church institutions likely lies somewhere between 10,000 and 20,000, according to the probe, which went back as far as 1945. The commission behind the investigation was set up last year by the Catholic Church under the leadership of a former government minister, Wim Deetman, a Protestant, who said there could be no doubt church leaders knew of the problem. "The idea that people did not know there was a risk ... is untenable," he told a news conference.