Mass incarceration is a term used to refer to the fact that in the 21st century, the United States' incarceration rate is exceptionally high compared to that of other countries and to its incarceration rate earlier in its history. As of July 7, 2015, the United States' prison population rate (716 per 100,000 people) was higher than that of any other country in the world. From 1980 to 2010, the United States' incarceration rate more than tripled from 220 to 731 per 100,000 people. Even though the United States' crime rates have been declining since the early 1990s, the United States' incarceration rate has increased over most of the time since then.