The letters of the alphabet exhibit five varieties of symmetry (or non-symmetry):

A M T U V W Y have left-right (vertical) symmetry (.272) v
B C D E K have up-down (horizontal) symmetry (.218) h
N S Z have 180 degree (rotational) symmetry (.137) r
H I O X have all three symmetries (.205) a
F G J L P Q R have no symmetry (.168) n