Private prisons are a $5 billion industry that employs more than 33,000 people, per the market research firm IBISWorld. Here's where they're most prevalent:

Note: States with no private prison population are as of December 31, 2015; Data was not available for Nevada, Oregon and Vermont; Data: Bureau of Justice Statistics; Chart: Chris Canipe / Axios

Why it matters: The Obama Justice Department pushed to end the federal government's use of private prisons. But the Trump administration's decision to rescind the order has led the industry to hope for a resurgence, though some states like New York, Iowa and Illinois, have ended their use for state prisoners.

Key takeaways:

• In 2015, 126,272 people — or about 8% of the country's prison population — were housed in private facilities.
• The states with highest shares of inmates in private prisons were New Mexico (42.2%) and Montana (40.4%).
• Texas alone housed 14,293 inmates in private prisons.
• Per IBISWorld, the private prison industry has been growing at a rate of about 1% per year since 2012.
• If a state has a private prison population of zero, that does not necessarily mean that the state does not have such facilities, per the Bureau of Justice Statistics. The data simply indicates that no prisoners were held in private prisons at the end of the year in 2015.