Does anyone know the percentage of searchers that use wildcards in their queries?

[TargetClick]

I am trying to figure out the number of searchers that use wildcards (*) in their searches.  I cannot find much information about a percentage or even ballpark figure.  If there is not information on that, what is the percentage of users that use the 'advanced search' options?  I am guessing the numbers would be semi-similar.

Thanks!

[BenFox]

I don't numbers as a % of the total market but after having a quick look at a large sample on an e-commerce site I found around 1 wildcard per 70,000 searchers. Of those only 1 in 20 actually look like they're deliberately using it as a wildcard.