There are two schemes under which prisoners may be released before they have served half their sentence. The latest published figures show that of a total of about 800,000 prisoners who came through the system between 1999 and the end of 2008, some 159,000, or 20 per cent., were released under the home detention curfew scheme. Of about 200,000 prisoners who came through the system from June 2007 until the end of September this year, approximately 70,000 were released under the end of custody licence scheme.