I hope that you are not really trying to sell this to us as how "good" a racial is. First of all you'd have to divide the whole thing between Horde and Alliance since the Alliance does not get to choose the Horde races and thus their races and the Horde doesn't get access to Alliance racials.
Overall from your data the population would be 47%/51.1% which puts both factions fairly close and makes me wonder where the missing percentages went. But seeing how your source is wow graphs a site which has proven unreliable and at times giving conflicting data we can just ignore it.
Seeing as how about both factions are about equal one should ask themselves whether the huge dominance of humans in the Alliance is being caused by the human racial being overpowered or more likely the only viable choice for ANY class that can play a human. The second is more likely since your data puts the Horde overall at a slight advantage. So the better distribution on Horde side is likely caused by a wider range of viable racials and different ones being desirable by different classes.
In fact in the Alliance certain racials such as Shadowmeld, Stoneform and Draenei Heal are solely boosted by the fact that most of these players will play a class that simply can't be human. So completly useless abilities such as shadow meld get artificialy boosted by the fact that for the longest time druids were the only class on Alliance side that could be druids and even nowadays are only challenged by worgen with equal if not more so useless racials for druids.