one of my high-volume sites is just over 25% mobile users now
I find this amazing since I have had several .mobi sites up for 3.5 years now, they are prominently linked through their respective example.com sites yet no one uses them and I mean maybe a couple of hundred uniques per month.
I decided recently not to renew quite a few of them because of this plus after viewing my main sites on a mobile they looked pretty good anyway.
Whether it is to do with my main niche subjects I am not sure since they are principally trade images and technical specifications therefore maybe you'd have to be a little desperate to want to do this on a mobile?
Just goes to show how niche subjects can vary possibly?