Sentenced prisoners in New Zealand

Sentence: A sentence is a punishment given by a judge. A prison sentence is the most punitive sentence a judge can impose. Some sentences such as home detention are designed to be both punitive and have a rehabilitative aspect to them.
Sentenced prisoner: People in prison for a custodial sentence. Sentenced prisoners are those convicted of a crime and sentenced to imprisonment.

This data measures distinct sentence periods, not unique offenders, that is, the number of new sentence period starts within a financial year. If an offender starts more than one sentence period within a year then the offender is counted more than once.
A person is counted once for the most serious offence category for which they were prosecuted.
Information on the sex and ethnicity of an offender is recorded by Corrections. Age is calculated based on the birth date as collected by the prosecuting authority (mostly New Zealand Police) at the time a person is arrested or prosecuted.
The durations shown are court-imposed lengths and not actual time spent in prison.
A prison sentence that is subsequently cancelled on appeal is still included in these statistics, as the offender had spent the time in prison.

http://www.corrections.govt.nz/__data/assets/pdf_file/0007/835693/Trends_in_the_Offender_Population_201415.pdf

The prison sentence data come from the Department of Corrections' data warehouse. From 1999, the data has been sourced from the Department of Corrections' Integrated Offender Management System (IOMS).