Pot is getting more popular.

As we noted in this space last week, a majority of the American public -- 52 percent -- said marijuana should be legal, the highest mark ever measured in Pew polling.

While pot use is still illegal under federal law, two states in November 2012  -- Colorado and Washington -- legalized it for recreational purposes.

And, the general direction of state laws regarding marijuana -- whether it's legalizing it, legalizing it for medicinal purposes or decriminalizing it -- is clearly moving in the direction of leniency.

The best visualization of that trend that we've seen comes courtesy of the Atlantic Wire's Philip Bump and Elspeth Reeve. Beginning in 1970, the map features the year-by-year progression of marijuana laws across the country.