Sergeants and lieutenants laugh at that. The criminal justice system is going after traffickers, not users. There are very rare and unique situations of imprisonment for usage, but when the stories are checked out they almost invariably turn out to be contrived, a partial story, misleading, or don't deal with other evidence against the accused. The data are complicated. There are state, federal and local statistics.
Many categories overlap.
There are different laws in different states. One reason that it's tough to make it to prison for simple drug possession is that small amounts hardly ever merit incarceration. But even 50 grams can translate into 50 personal units, a quantity more appropriate for a fledgling business than a simple recreational toot. Looking at state statistics, Reynolds notes that 70 percent of prisoners on drug charges are there for trafficking, vs. 27 percent in for possession. There may indeed be a case for reform in our drug laws.