daniela mock-zubia and sofia gradersi, 12th and 10th candidates toial discuss prison reform and a videoitled "rethinking reform: prisons in america." use ago there were 500,000 people behind bars in america -- 30 years ago. today there are 2.2 million. is home to 5%tes of the world's population by 25% of the world prisoners. every year, we spend $80 billion to keep people locked up. ♪ >> the prison systems around the united states have changed radically in the last 20 to 30 years. but let me address arizona. 20 years ago, our prison population was about 20,000 people. now our state prison system is over 40. the composition of the prison population has also genetically changed. the vast majority of our prisoners are there for nonviolent offenses. >> the evolution of the prison system, what i saw from the outside being a native, is growing up there was only the arizona state prison. you'd see the prisoners in the community, trustees they would let out during the day to work on prison farms or ranches or in some other regard, cleaning up highways. >> while in prison, the conditions i was s

daniela mock-zubia and sofia gradersi, 12th and 10th candidates toial discuss prison reform and a videoitled "rethinking reform: prisons in america." use ago there were 500,000 people behind bars in america -- 30 years ago. today there are 2.2 million.