I used to work for a developer in Saint Louis. They said their showing rate was high, and I estimate they showed one listing about 3-4 times per week. I'll link to their site so you can get an idea of the quality of the condo's, but you also have to take into consideration location (obviously). Really the best way to find an answer to this question is probably through a competitor. I don't think it would be morally wrong to pose as a prospective, and then ask your question once you've feigned interest in a listing.

Metropolis Condos St. Louis

We've had 2-3 showings per week on average for each of our listings this summer. Deals are happening but at a slower more drawn out pace than this time last year. That being said, the next few weeks are expected to be much slower since many folks are out of town on vacation. I expect the traction to pick up again beginning September 8th when folks realize this is a great time to buy and if they want to get in before winter sets in they should get busy. Advice: Don't loose hope...just hunker down and wait a while. Now if you've not seen 2-3 showings a week prior to this time, you may be priced too high and thus your listing may be "stale".

You may have 0 if the price is too high.
You may have good home and good price and still not have to much activity in current market.
I had 5 showings for a condo in Willowbrook in 7 months and finally is under contract.
There is few less expensive but the top condition won the buyer attention.

I have a townhome listed and it is getting about 2 showings a week. My other listings are detached and are getting about the same, here in Schaumburg. The price and picture quality has a lot to do with the action.