Do you mean sick as in not eating/high temp/generally miserable/?
Or do you mean sick like snot?
Cause if you mean snot, pretty much constantly through winter
BUt as for true ilness, like going to the doctor, maybe once a year.
In our first year of FDC, we did have a few trips to the docs with temps and rashes, but mostly that was just me freaking out. (and FDC having really strict policies, current daycare is much more lax)