Christians ONLY: What is your success rate using Chick tracts?

For those of you who don't know what these are, they are small comic book type tracts that teach about sin and the destruction sin brings and also they teach the way to salvation with the sinnner's prayer. They are so well-written, nobody with a brain could ever walk away from reading one without repenting or else rejecting God outright knowing He's real. I have had good success with them, people pick them up and read them. I wish I knew how many convert because of them. Do you have any idea of your success rate with them, if you use them?