1. e4, 1. d4, 1. c4, or 1. Nf3? Which opening move has given the greatest scoring percentage for White in World Championship Matches? Which opening move  out of 1. e4, 1. d4, 1. c4 and 1.Nf3 has given the best scoring percentage for White in World Championship matches? What are the percentages?
1. b3 has the greatest scoring percentage (100%), although it's statistically insignificant because it only appears in one game out of 1,506.

The successful openings played more regularly are: 

Nf3 (61.7%, 102 games)
c4 (59.3%, 129 games)
e4 (57%, 631 games)
d4 (55.4%, 632 games)

That data's compiled after downloading all 1,506 World Championship games from 1886 to 2013 from the chessgames.com WCC archive. Here's what Scid's Tree Window shows: