PyCon has been around 25% the last couple of years. For 2013 we accepted 114 out of 458 proposals, and in 2012 we accepted 95 out of 378 proposals.

For 2014 we're more than likely going back to 95 slots, and I'd expect the number of proposals submitted to be roughly the same or higher. That'll put us closer to 20%.

Plenty of mere mortals get on stage at PyCon. Speaking experience does hold some weight with reviewers, but a well organized and interesting topic will take you pretty far.