82 percent:
Authority for cited percentage is on Enough is Enough Sexual Exploitation Archives: "In 82% of online sex crimes against minors, the offender used the victim's social networking site to gain information about the victim's likes and dislikes. (Journal of Adolescent Health 47, 2010)"
62 percent: sic 65 percent
Authority for cited percentage is on Enough is Enough Sexual Exploitation Archives: "65% of online sex offendors used the victim's social networking site to gain home and school information about the victim (Journal of Adolescent Heatlh 47, 2010)"
Enough is Enough's Sexual Exploitation Archives has many other interesting facts.