Wow, If I lived in Brazil earning the same amount I do in England, I would be in the top 0.02%. The place where you live influences the final result.
I was checking it myself. It converts for currency appreciation, but your statement seems incorrect. A income of 500,000 in England makes you something like the ~800,000th richest; and on Brazil, only the ~1,900,000th richest. That's because the Pound is worth much more than the Real.
Also, it seems like I'm getting some BS statistics, unless the monthly salary of a doctor on Kazakhstan is actually 58 US Dollars. A quick Google search tells me it is about 2,600 US Dollars.