Data on MAPPA management and on the number of registered sexual offenders in England and Wales are available in the annual published MAPPA reports
http://www.probation.justice.gov.uk/output/page30.asp
The MAPPA annual report for 2007-08 is the most recent. A total of 5,788 registered sexual offenders were managed via MAPPA meetings between 1 April 2007 and 31 March 2008.