I see a lot of data expressed in GDP per capita
GDP per capita is the aggregated Gross Domestic Product of the entire country divided by its population. It says nothing about income or wealth distribution within this country. It is also NOT the mean of personal income in that country.
GDP per capita basically tells you how much does a country produce, normalized for its population.
a neat way that the CIA is actually using to push it's policy agenda
If you have nearly data over the median income of countries all over the world over the last 100 years
I don't and I doubt it exists. You can find estimates of median income for developed countries during the last couple of decades easily enough in the usual places, but beyond that the data is likely to be sparse to absent.
I don't and I doubt it exists.
If you don't have the data how would you go about comparing the wealth of different countries based on it? I don't see how those claims fit together.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.