That depends on price range. If you take ALL the Active/Sold single family homes(only) for the past 6 months here is a quick market statistics report.....
There are currently 982 Active single Familly homes in Naperville with an average of 256 days on the market.
In the past 6 months there have been 704 single family homes that have sold with an average of 136 days on the market and a List to Sales price of 95% but only 86% List to Sales price from Original List price.
The statistics are different for # of bedrooms, price range, attached homes, etc..
I hope this helps!