Not much of anything. I've never heard a local patch talkgroup used anywhere in IL (although I'm sure they are used occasionally), and I've only heard traffic on a detail talkgroup outside of the Chicago area MAYBE once. If I'm not mistaken, the local patch is to be used in an emergency when communication is needed with an agency that doesn't have access to StarCom, and it can be patched to whatever frequency or system it needs to go to. Use, I would imagine, is pretty low with most agencies having either an ITTF StarCom radio or ISPERN/IREACH to communicate with state.
Just 3 days ago, TG 30355 was heard in my area, although it's not carried on this tower so I believe in might have been patched from Mclean county for some reason.