The growth of the private detention industry has long been a subject of scrutiny. A recent eight-part series in the New Orleans Times-Picayune chronicled how more than half of Louisiana’s 40,000 inmates are housed in prisons run by sheriffs or private companies as part of a broader financial incentive scheme. The detention business goes beyond just criminal prisoners.

As a Huffington Post investigation pointed out last month, nearly half of all immigrant detainees are now held in privately run detention facilities. Just this week, the New York Times delved into lax oversight at industrial-sized but privately run halfway houses in New Jersey.

We’ve taken a look at some of the numbers associated with the billion-dollar and wide-ranging for-profit detention industry and the two companies that dominate the market: