This is the latest from the Center for Sex Offender Management:
"Without question, public demands for stringent sanctions, long prison terms, intensive monitoring, and other community protection measures are influenced by beliefs about the potential for sex offenders to reoffend. Determining the “true” recidivism rate for convicted sex offenders is hampered by under-reporting and under-detection, but the available data indicates that roughly 15-30% of adult sex offenders are known to recidivate, as measured by rearrest and/or re-conviction, during follow-up periods of 5-15 years.
"The findings of the current poll indicate that the public believes sexual re-offense rates are markedly higher. The majority of the respondents (72%) presumed that at least half, if not most, convicted sex offenders will commit additional sex crimes in the future. Indeed, one-third (33%) held the belief than 75% or more will reoffend."