Wednesday marked the first day that marijuana, in both medical and recreational forms, is legal in Oregon. Like in other states that have legalized the sale of pot, tax revenues on sales will likely add revenue, and the state will save money by prosecuting marijuana crimes at greatly reduced rates. Outside of black-and-white revenue streams, it can seem difficult to quantify just how much time and energy is spent on chasing pot crimes; decades of stigma and prosecution has spawned a prosecutorial infrastructure built around marijuana alone.

Just look at Chicago.

Over at the website Arrestchicago.org, however, all the time and effort that Chicago spends on prosecuting pot crimes is corralled into a couple of charts and graphs that automatically update based on the city's crime database. The results, while not necessarily surprising, are certainly sobering. According to data for the last 90 days, almost 20 percent of arrests have been cannabis related, making that the second most common reason Chicagoans are arrested after battery.

As for how this plays out in the criminal system, for the 2,814 cannabis-related arrests over the past 90 days, the site uses data from investigative and scholarly reports to estimate that nearly 8,500 police hours were spent filing arrests, and more than $7 million taxpayer dollars were spent staffing facilities, with 98 citizens being incarcerated. Moreover, the site calculates that 88 percent of all cannabis-related arrests over that 90-day period are for possession of 30 grams of pot or less, and about 76 percent of those arrested were likely African-American, though cannabis use between Blacks and whites is equal, according to the Washington Post. These percentages are not surprising when you look at Arrest Chicago's heat map, which visualizes the arrests; the red and orange areas where there are more cannabis-related arrests are on the West Side and South Side of the city, predominantly Black neighborhoods.

arrestchicago.org - arrestchicago.org

The city supposedly decriminalized marijuana possession.

What makes these stark numbers surprising is that Chicago passed legislation in 2012 to decriminalize marijuana. The idea was that violators would not be arrested and only hit with fines. The city, however, has had trouble changing its practices. According to a study in 2014, pot arrests are down since decriminalization, but 93 percent of misdemeanor marijuana possession violations result in arrest. That's according to Roosevelt University's Illinois Consortium on Drug Policy.

"Like any new process, it has taken time to implement the ordinance, and we believe there's certainly much more work to be done on full implementation," a Chicago police spokesperson told the Chicago Tribune in 2014.

For more information and to check out data visualizations for cannabis-related arrests over 7, 30, and 90 day periods, head over to Arrest Chicago.