Here are some statistics from a US site.
victimsofcrime.org/media/reporting-on-child-sexual-abuse/statistics-on-perpetrators-of-csa
Child Sexual Abuse Statistics
The prevalence of child sexual abuse is difficult to determine because it is often not reported; experts agree that the incidence is far greater than what is reported to authorities. CSA is also not uniformly defined, so statistics may vary. Statistics below represent some of the research done on child sexual abuse.
The U.S. Department of Health and Human Services’ Children’s Bureau report Child Maltreatment 2010 found that 9.2% of victimized children were sexually assaulted (page 24).
Studies by David Finkelhor, Director of the Crimes Against Children Research Center, show that:
1 in 5 girls and 1 in 20 boys is a victim of child sexual abuse;
Self-report studies show that 20% of adult females and 5-10% of adult males recall a childhood sexual assault or sexual abuse incident;
During a one-year period in the U.S., 16% of youth ages 14 to 17 had been sexually victimized;
Over the course of their lifetime, 28% of U.S. youth ages 14 to 17 had been sexually victimized;
Children are most vulnerable to CSA between the ages of 7 and 13.
Statistics on Perpetrators of Child Sexual Abuse
Offenders are overwhelmingly male, ranging from adolescents to the elderly (page 171).
Some perpetrators are female. It is estimated that women are the abusers in about 14% of cases reported among boys and 6% of cases reported among girls.
Approximately one-third of offenders are themselves juveniles (page 172).
23% of reported cases of child sexual abuse are perpetrated by individuals under the age of 18 (page 3)
Only 14% of children who suffered sexual abuse were violated by an unknown perpetrator (page 172).
60% of children are sexually abused by someone in their social circle. Hence, the phrase “Stranger Danger” is misleading (page 172).
Meta-analysis estimates that 14% of sexual offenders commit another sexual offense after five years, 24% after fifteen years (page 172).
Child Maltreatment 2010 reports that 6.2% of child abusers sexually abused a child (page 77).
40-80% of juvenile sex offenders have themselves been victims of sexual abuse (Advances in Clinical Child Psychology, page 19).