Thats only if they click on the banner. IMO I say about one percent who visit the page will do that. Unless you can find statistics somewhere else that has a more solid base. That would be a good project for someone to do research on.
These figuares will be based on
the size of the ad the freq rotation of the ad (how many cycles before we see GNF) the colors of the ad (for attraction ie which stands out more) cultural use of colors (red for warm,etc) http://desktoppub.about.com/od/choosingcolors/p/color_meanings.htm the placement of the ad (bottom,top,right,left)