How many footsteps raise a Pokemon's happiness by 1?

Question

I heard you can raise a Pokemon's happiness by walking a lot. How many footsteps excatly raise a Pokemon's happiness?

Answer 1

#128
Sometimes raises a Pokemon's happiness, +2 between friendship of 0-199 and +1 between 200-255. There is no in between, you can't get a +1 from walking if your happiness is below 200, you'll get +2.