Distribution of adults with college degrees around the US

This graphic comes from today's New York Times; it illustrates a story about the changing distribution, nationwide, of college graduates. Increasingly, college graduates are concentrating in urban centers. The graphic is interesting for two reasons. First, the shape of the curve is changing: in 1970, 12% of adults in US metropolitan areas had college degrees - but the curve was steep, and most areas were within 5 percentage points of that percentage. in 2010, 32% of adults in metro areas had college degrees - but the shape of the curve has changes, with many more cities falling outside 5 percentage points, both above and below.

Second, notice that I have said that "some percentage of adults in US metropolitan areas" to describe the chart. The Times says "In 1970, 12% of adults had college degrees in US metro areas." This awkward language is confusing, I had to read it several times when I read the print version this morning, and it was only when I looked at the data the Times provides, a list of the metro areas with share of population with college degrees, that I understood what the paper was trying to tell me. This confusion could have been avoided with better wording. Am I right? Let me know in the comments if you think I've misinterpreted here.