When I try to look into standard of living in a given country, I try to find median income figures. I can almost never find them. Instead, all of the data I can find is about average income, GDP per capita, etc. This data is (I think) pretty useless in determining how most people live, because in many of the countries I am looking at, a small number of people receive a disproportionate amount of income.
Is there a reason why median income is not used as the primary figure?