How are the numbers at Globalrichlist.com?

At http://www.globalrichlist.com/ you can enter the amount of money you make and it tells you how much you make compared to the rest of the world. I entered in my small sum and was startled to see that I am in the top 12%. Here’s how they calculate it: http://www.globalrichlist.com/how.html

So are these numbers correct?

You may think you’re making little compared to others in the rich first-world country you’re in, but compared to others living in poor countries (and a considerable portion of mankind lives in the Third World), you’re rich.
Of course the general costs of living in poorer countries are lower, so the absolute amount in dollars doesn’t tell you everything, but all in all you can be sure there are lots of people poorer than you.

Well - as one example - the vast majority of the UAE’s three million residents are subcontinental expatriate workers earning around US$25 per week, and they are considered comparatively wealthy back home in northern Pakistan, etc.