I only took up photography just over a year ago when my father gave me his old, dusty Rebel XSi for Christmas. All of these counts are the only pictures I've ever taken!
Lightroom says 17,537 clicks in 2012 - 1974 on my since-sold Rebel XSi and 14,205 on my D700. 1,283 on my girlfriend's D5100 and 75 on my dad's Olympus OM-D E-M5. Of those, I marked 3,138 as keepers for an overall rate of 17.9%.
As I suspected, the Sigma 30mm/1.4 had the vast majority of shots on the XSi and my 50/1.4 has the most on my D700, though my 24-70 is rapidly catching up!
I almost upgraded to a 5D2 after getting sick of the Rebel, but decided to go for a D700 instead since I would have had to sell my only good lens regardless of which brand I went with.