Source: Prison Population Statistics, Grahame Allen and Noel Dempsey (Number SN/SG/04334, 4 July 2016)
The annual average is the average of the 12 month end populations.
2014 and 2015 data is calculated from quarterly reports.
MoJ, Offender Management Statistics Quarterly, October-December 2013
MoJ, Offender Management Statistics Quarterly, various years