It depends on the day. Rec classes are generally 7:1 or better.
For team, it could be as high as 16:1, but if that is the case, it is only one group and there is often a "float" coach that can step in to any of the groups.
Typically though:
Level 3 - 11:1 or better.
Level 4 - 9:1 or better
Level 5 - usually mixed with Level 4 at 15:2
Level 6+ and Xcel - 16:1, but they are rarely all there and 4 are currently out injured, not all gym related... so currently 12:1 or better.
Highest I have seen is 10:1, and that's only for some events. There is usually an extra coach or assistant to help out for at least part of the time. Normally 4-8:1.
for JO we have 4 coaches. one is strictly level 3 and 4 (she's also the head excel coach). one is 4 and 6 and then the HC floats between 4-9 but mostly upper levels. although he has been known to get out on the floor with the 3s to fix the floor routine mistakes. the AHC is mostly 7-9 but she also helps out with the 6s. i'm not really sure what our ratio is at any given time though since not everyone practices on the same nights/times. the former gymnast who did our 6 floor routines comes in on most tuesdays to help out too. she's a teacher and i think this is her way of keeping one foot in gymnastics.
Ours varies widely. Last year for my daughter it was 1-2 coaches for 5 kids (one coach was always with them, the second would help out after her group was done). This year it's 1 coach for 9 kids, with some help for the last half an hour or so from a second coach and occasional help from some of the optional coaches.
Excel probably has 25-30ish girls and maybe 4 coaches?
Rec classes are capped at 1:8.
1:8 is their max and most groups throughout the day are right at that- from rec on up through xcel and jo.
there are also a couple of morning jo groups (TOPS & HOPES) who get 1:4 several times a week.