Pygame FPS faster than what I want

Question

I am trying to run a game at 80 fps but I am getting 83 fps?! What's going on?

while 1:
  start = time()
  clock.tick_busy_loop(80)
  self.update()
  fps=int(1./(time()-start))
  print fps, 'fps'
>> 83 fps

Answer 1

Resolution of pygame clock = 1 msec
80 fps = 12.5 msec
83 fps = 12 msec
int(12.5) = 12