To make up for all those nasty Word Play puzzles, here's a nice, simple sequence puzzle.
What is the next number in the following series?
50, 33, 25, 20, 17, 14, 13, 11, _

You can validate your puzzle solution with certitude.
The final is on the side of a road. Park carefully and be aware of the traffic. Final is a micro, so please BYOP and write small