Just a quick ref:
http://bjs.ojp.usdoj.gov/content/pub/pdf/rsorp94.pdf
Statistics can be difficult... at first appeance, the numbers seem high like this: "Within 3 years following their release, 38.6% (3,741) of the 9,691 released sex offenders were returned to prison."
and " the study found that 43% (4,163 of 9,691) of the 9,691 released sex offenders were rearrested"
But it's misleading. Read the statistics carefully.
"Of the 9,691 released sex offenders, 3.5% (339 of the 9,691) were reconvicted for a sex crime within the 3-year followup period."
Most of the returns were not related to same sex offense but a different crime.