On the heels of its acquisition of Arbitron, Nielsen has added audio measurement to its mix, including some data on radio listening to its latest cross-platform report [download page]. According to Nielsen, more than 9 in 10 Americans listen to radio on a weekly basis, with those figures highest among Hispanics (94%) and African-Americans (92%). Interestingly, a comparison of user demographics reveals that radio’s adult audience has a very similar age profile as mobile’s audience.

Specifically, 12.8% of AM/FM radio’s adult audience is in the 18-24 demographic, exactly the same percentage as with mobile’s audience. Moreover, 34.8% of the AM/FM radio audience is aged 25-44, as is 34.5% of the mobile audience.

Radio’s audience looks far more similar to mobile’s audience than TV’s, which skews much older. Among TV viewers, a relatively small 21.6% are in the 18-34 bracket (compared to 30.2% for radio and 30.1% for mobile). By contrast, 43.5% of TV viewers are aged 55 and older, compared to 33.4% for radio and 33.9% for mobile.

The similarities between radio and mobile tend to dissipate when sorting by other demographic factors, though. While 31.6% of AM/FM radio listeners are college graduates, that figure rises to 41.5% among mobile users. And radio’s audience appears to be slightly more heavily skewed towards African-Americans than mobile (12.7% vs. 11.4%) with the opposite true for Hispanics (12.7% vs. 14.1%).

On average, Americans spend 60 hours and 42 minutes per month listening to AM/FM radio, per the report, compared to more than 150 hours for traditional TV. Radio’s audience continues to grow, according to a September study from Arbitron, which found that radio reaches 242.2 million listeners aged 12 and older on an average weekly basis, an increase of more than half-a-million listeners from the same period last year.