A/HRC/12/23 page 10 39. According to an American study, 92 per cent of offenders were in possession of images of minors that emphasized their sexuality or images of minors involved in explicit sexual activities; 80 per cent of the images depicted anal penetration of a child, including oral sex, and 21 per cent had child pornography material depicting violent scenes, including rape, bondage and torture of children. 40. An Australian Federal Police study on sexual predators on the Internet yielded the following statistics: Activity Incest or implicit incest Torture, violence, bondage, etc. Humiliating or degrading activities (use of urine, excrement, etc.) Zoophilia Number 16 13 9 Percentage 32 per cent 26 per cent 18 per cent 9 18 per cent 41. Most producers of images of sexually exploited children are known to their victims: 37 per cent of offenders are family members, 36 per cent acquaintances; more than 30 per cent of individuals found guilty of possessing child pornography lived with minors and more than 50 per cent of those individuals had access to minors at home, at work or in their social environment. Furthermore, abusers had known the child for a long time before initiating sexual activity: in 39.1 per cent of cases the first sexual contact occurred more than one year after initial contact.4 42. There are many types of users of child pornography sites: consumers, producers, distributors, abusers, paedophiles, etc. While a person who visits child pornography sites is not necessarily a potential child abuser, it should be emphasized that statistically speaking most predators arrested for molesting or raping children were in possession of significant collections of child pornography. 43. Child pornography is either produced offline for subsequent circulation on the Internet or live for online viewers. The exact number of images in circulation is difficult to determine, given the availability of child pornography on peer-to-peer (P2P) networks (social networking). 44. The production and distribution of criminal child pornography depicting abuse of children has an estimated value of between $3 billion and $20 billion. 45. There has also been a significant increase in Internet solicitation of children for sexual purposes. According to the Pew Research Center, 60 per cent of adolescents have received messages from strangers, not always of a sexual nature, and one child in four found this normal. Likewise, according to the FBI, the number of online assaults on children increases by 4 NCMEC contribution to this report, 2009.