https://i.imgur.com/whWAVs3.jpg
The strong majority of all prisoners are in for violent crime and property crime. Public order offenses (which includes eg weapons and DUIs) are nearly as large as all drug offenses.
There are about 60% as many people in state prisons for just burglary, as all drug offenses.
In 2015, only 3.4% of people in state prisons were in for drug possesion of any type. Marijuana would be a small subset of that figure.
