The number of people held in U.S. prisons has risen eightfold since the 1970s, when Books to Prisoners was founded. Today there are more than 2.2 million U.S. prisoners—nearly 25% of all the prisoners in the entire world. At the same time, the growth of privatization of prisons, as well as shrinking state budgets, has whittled prisoner access to books. When times are tight, anything regarded as a benefit for the incarcerated population is likely to be first on the chopping block, and some prison librarians say their budget for new books is zero. For that reason, by sending books to prisoners on request, BTP is helping to fill a huge unmet need.