Looking at the number of frequent visitor index cards sitting behind the counter I thought "damn!, probably 2000 cards". Making a few estimates like mongers visiting 4 shops and maybe 50 shops in NNJ and male population of the mongering age being 2,500,000 that puts the active participation rate, as mentioned above, in the 1% range. I've read that as much as 10% have tried it. Five years ago I had no clue.