labor - Wages went up 7.94% over 2006, Mercer, or not?

Recruiting in China comes with a few figures on average wage increases in China over 2006. According to human resources firm Mercer salaries in China did not rose 8 percent, no only a poor 7.94 percent.
There are a few figures more, but I stopped looking into those details when I found some very odd contradictions. I'm very bad in figures myself, but when the average wage rise is 7.94 percent, why then sees Shanghai "the strongest pay surge" with 7.7 percent? It just does not add up.
Anyway, I must be today in a "so-what" mood, since I think all these figures are too generic to makes sense. Even when some are split, it give only a very unclear picture of what is really happening.

Update: Xinhua comes with exactly the same article and exactly the same mistake, but they attribute it to the China Daily. Recruiting in China failed to come up with such an attribution and that is wrong for at least two reasons. First, you steal the work of somebody else, but that seems hardly a good argument talking about China. Secondly, when you copy-and-paste a stupid mistake, you look foolish in stead of the original author.