As of December 31, 2006, the imprisonment capacity of penal institutions was 79,375 including 62,077 for sentenced inmates, and the actual number of imprisoned inmates was 81,255 including 71,408 sentenced inmates.
  Fig. 2-4-1-1 shows the trends in the rate of imprisonment (the rate of imprisoned inmates against the imprisonment capacity) over the last 20 years.
  As of December 31, 2006, the rate of imprisonment slightly decreased from the same time of the previous year due to an effort to raise the imprisonment capacity. However, the number of inmates has been on an upward trend, and penal institutions are still overcrowded. Among 75 (main) penal institutions, 53 institutions (70.7%) accommodate inmates exceeding their capacity (Source: The Correction Bureau, Ministry of Justice; see this Chapter Section 4 for countermeasures to overcrowding).

Fig. 2-4-1-1  Trends in the rate of imprisonment of penal institutions (As of December 31 in each year in 1987-2006)