Here are the two Nintendo handhelds, now with the platform identified on each graph:
The relatively small number of games rated M (for "Mature") clearly identifies the two Nintendo platforms. The distinguishing feature between the two is the rating category E10+, which wasn't created until 2005, far into the life of the Game Boy Advance. Since the E10+ rating has existed for nearly the entire lifetime of the Nintendo DS, more of its games have received that rating.
If one considers the E and E10+ ratings as approximately the same, then the two Nintendo handhelds exhibit very similar ratings distributions. Fewer than 1% of the games for either platform were rated M and approximately 10% received a rating of T (for "Teen"). The rest were either E or E10+.
Now, here is the PlayStation Portable's distribution:
From the beginning Sony has aimed the PSP at an older demographic, and the ESRB ratings of its games reflect that strategy. Almost 9% of its games are rated M and nearly 35% are rated T.
I found some interesting comparisons in the last generation of consoles: the Sony PlayStation 2, the Nintendo GameCube, and the Microsoft Xbox. As before, take a minute to examine the graphs sans labels (again in random order) and try to reason which graph belongs to which platform from just the rating distributions.
The answers are given on the next page.