There's been a population boom at federal prisons since the 1980s. A big one.
But before looking at what happened in the '80s, it's worth first delving into the history of the Federal Bureau of Prisons for some context.
The bureau, which manages federal prisons, was established in 1930 and charged with the "management and regulation of all federal penal correctional institutions."
At the time, there were 11 federal prisons. By 1940, there were 24 facilities and 24,360 inmates. The number of inmates remained pretty much the same for the next 40 years, although the number of facilities grew to 44.
In mid-2018, there were 183,881 federal inmates serving time at 122 prisons or "institutions," as the BOP prefers to call them. They are divided into six categories: minimum, low, medium, high, complex and administrative.
That brings us back to the question: What happened between 1980 and today? The answers are pretty simple: mandatory minimum sentences and drugs.
The Sentencing Reform Act of 1984 established mandatory sentences and abolished parole for federal inmates. It was beefed up with additional mandatory measures in 1986, 1988 and 1990. Add to that efforts to combat illegal drug use — crack, powder cocaine, meth and more — and you imprison a lot more people for a lot longer.
Here are some facts about people behind federal bars:
— 46.2 percent were convicted of a drug offense.
— 17.5 percent were convicted on charges relating to "weapons, explosives, arson."
— 79.8 percent are U.S. citizens; the next-largest group is Mexican citizens at 12.9 percent.
— 67.2 percent are non-Hispanic.
— 93.1 percent are male.
— 25.2 percent of federal inmates are serving five to 10 years; 21 percent are serving 10-15 years. Only 2.8 percent are serving life.
The age of people serving time is especially interesting: 19 percent of the inmate population is 51 or older.
The DOJ estimated that the Bureau of Prisons spent approximately $881 million, or 19 percent of its budget, to imprison aging inmates in 2013. The main reason they're more costly: medical needs.