10%, maybe a little more. The problem is it is really random. Some days 0, some (very rare) days $200. Ads are much more predictable.
I’m seeing 1/10 of ad revenue (to 1/15th) for a novelty type app - and this is with Tapjoy.
Earlier with GetJar I was getting slightly more (oddly enough ! - since I thought GetJar etc. is slow etc. - but it seems GetJar pays slightly more per download maybe).
My guess is this is still open to improvement i.e. if you have reminder or some such (awarding virtual coins on return to app is one such method - as discussed on this forum before - and also helps retention etc. supposedly).
The problem is that any highlighting you do for people to try IAP is at the cost of something else - i.e. if you show a reminder screen - you could have shown an ad there instead - and that might earn you MORE reveneu (!) - this is the odd mechanics of app consumer behavior.
For this reason any way to highlight availability of IAP which DOES NOT distract from ads is a positive - so awarding of coins for returning to app etc. is one such way in that it (I assume) gives a warm feeling to user (and you don’t erode your goodwill - which you can use to show an interstitial ad then later).
After this post, I increased the frequency of ads and guess what I am going great. Increased revenue. Remove ads is a license for showing ads in top gear. 