We lost about an inch this past week. It was super hot. I notice more loss when the cover is off...for obvious reasons. We keep our pool at 92 or above so at night we probably lose some due to evaporation.
This map shows annual pan evaporation rates across the country where it's around 55" in Illinois. That would be 0.15" per day, but evaporation is higher in the summer because the pool water is often heated and the air is usually drier. It also depends a lot on wind. I usually double the annual amount for a rough summer limit so that would be 0.3" per day, but actual amounts would usually be less than that.