Let's see if I can attempt to make a more accurate look at what types are getting used in OU. 
 
1) This uses December's OU stats
2) Each pokemon is assigned a number based on their usage rank, #1 gets 100 points, #2 gets 99 points, #3 gets 98 points, etc. 
3) Dual types count as the same value, but give points to both types (ie: scizor gives 100 points to both Bug and Steel)
4) It's not meant to be entirely accurate, this is just what I thought of on the spot. However, I do think it paints a pretty good picture of the type usage in the metagame
 
Top 20:
 
(474)Steel -----100 98 96 95 85
(360)Water ----99 91 89 81
(360)Dragon----97 92 88 83
(354)Psychic---95 89 88 82
(191)Grass-----98 93
(185)Bug-------100 85 
(183)Flying-----97 86
(181)Rock -----94 87
(180)Fighting---93 87
(180)Fire-------96 84
(178)Ground---92 86
(94)Dark------94
(91)Electric----91
(90)Ghost-----90
(90)Poison-----90
(81)ice--------81
(0)Normal----
 
Top 50:
 
(727)Steel ----100 98 96 95 85 73 64 59 57
(711)Water ----99 91 89 81 79 75 70 65 62
(667)Psychic---95 89 88 82 78 69 57 55 54 51
(597)Dragon----97 92 88 83 67 63 55 52
(588)Flying----97 86 80 73 70 68 58 56
(509)Fighting--93 87 76 75 64 61 53
(426)Ground---- 92 86 74 60 58 56
(333)Fire------96 84 77 76
(317)Grass-----98 93 72 54
(294)Poison---- 90 79 72 53
(289)Electric--91 71 68 59
(262)Bug-------100 85 77
(222)ice------- 81 74 67
(181)Rock -----94 87
(157)Dark------94 63
(155)Ghost-----90 65
(66)Normal---- 66
 
Edit: There are a number of notable threats ranked 51-60, and I probably should have done this list as the top 60 and not the top 50, but I'm too lazy to go back and change everything for them now. 
 
Steel, Water, Dragon, and Psychics are clearly the most present types in the metagame by a large margin. Surprising? Not really. But it is cool to see them with stat weights attatched, imo. Steel does beat out Water though in both comparisons here.
 
 
 
 
Or you may choose to look at it as an average of the ranking placement within each respective type. This shows us which types average out to be higher on the list than others. This type of comparison would probably work better using the top 100 or something, as it favors types that only have a few pokemon that are at the top of the list, ie rock, which only has 2 pokemon within the top 50, but both are very good vs Psychic which hold many spots in the metagame and are quite common, but many are lower ranked. This list shows that.
  
(using top 50 averages): 
Rock: 90.5
Bug: 87.333
Fire: 83.25
Steel: 80.778
Grass: 79.25
Water: 79
Dark: 78.5
Ghost: 77.5
Dragon: 74.625
Ice: 74
Flying: 73.5
Poison: 73.5
Fighting: 72.714
Electric: 72.5
Ground: 71
Psychic: 66.7
Normal: 66
 
Take the meaning of any of the above stats however you want.