I found a fun free (though, do donate) app for analysing your photo statistics. You can get it at http://www.vandel.nl/
I ran it against the 6,500 photos I took in 2014. (Yes, I was surprised I had that many files for last year too).
Looking at the focal length there's a massive spike for 40mm. I'd imagine I use my 50mm prime more than anything else which leads me to suspect it gets recorded as slightly less and then reported at 40mm.