This site allows you to check out the play history from KCRW -- going all the way back to 1992, the earliest data I could scrape from KCRW. You have the option of viewing the play history via the many hosts of KCRW, or the artists and songs played over the years. By default, I filter for just the last year so my database queries don't take forever to load on your first experience.
One long term dream plan is to open access to the database with an API so one could submit arbitrary queries if one was so inclined. But this is a side hobby and for now there's very simple viewing options.
I'd recommend the desktop experience because I haven't yet figured out a way to make the plots display properly on small phone screens. So, buyer beware.
Damien helped with cleaning up of the site's database after a few years of watching it flounder. He's an ok web programmer and you can find his blog here.
"I didn't 'clean up', thanks. This site was a slow ass monstrosity that I brought to somewhat acceptable speeds, you're welcome, nottobeforgetting sage advice throughout its development." - Damien
For updates and/or discussions of interesting observations, read the KCRW-relevant posts on my blog.