In reality quite a bit less if the signal is less than perfect though.  Always a tradeoff between capacity and coverage.  No different than you addressing a room with 220 people in it, one at a time is easy, but if the back row is faint, or the front row is always noisy, or people just insist on talking over each other....you get a lot fewer conversations completed.

  @Shery1 

Also, if that 225-outdoor, is being used in a mesh, as they usually are, then your high capacity 5.8G band can be become very constrained based on what else is happening in the mesh.  Honestly you can usually bank on about 30-50 successfully sharing most modern APs operating in a reasonable environment with modern clients.  Some APs are designed for higher density applications (like TPlink's HD series, but to my knowledge, there are no outdoor versions of those).