Long-term trends

Over the last fifteen years, most OECD countries have experienced a continuous rise in their prison population rates. On average, across the 30 OECD countries, this rate has increased from a level of 100 persons per 100 000 unit of the total population in the early 1990s to around 130 persons in 2004. The prison population rate is highest in the United States, where more than 700 per 100 000 population were in prison in 2004: such level is three to four times higher than second highest country (Poland), and has increased rapidly. This increase extends to most other OECD countries. Since 1992, the prison population rate has more than doubled in the Netherlands, Mexico, Japan, the Czech Republic, Luxembourg, Spain and the United Kingdom, while it appears to have declined only in Canada, Iceland and Korea.

There are large differences across countries in the make-up of the prison population. On average, one in four prisoners is a pre-trial detainee or a remand prisoner, but these two categories account for a much higher share of the prison population in Turkey, Mexico and Luxembourg. Women and youths (aged below 18) account, on average, for 5% and 2% of the prison population respectively. A much larger share of prisoners is accounted for by foreigners (close to 20% of all prisoners, on average), with this share exceeding 40% of the total in Luxembourg, Switzerland, as well as Australia, Austria, Belgium and Greece. In several countries, the rapid rise in the prison population has stretched beyond the receptive capacity of existing institutions; occupancy levels are above 100% in more than half of OECD countries, and above 125% in Greece, Hungary, Italy, Spain and Mexico.