The link below from Wikipedia shows ranking of per capita income by nation. The United States is ranked number nine on all three rankings. The rankings are made by the International Monetary Fund, the CIA, and the World Bank.
A number of the countries ahead of us include city states such as Monaco, Luxembourg, Quatar, and Lichtenstein. Cities generally have higher per capita income then their rural hinterland, and in these situations the rural hinterland is in an adjacent country, and thus not counted in the results.
Non city-state countries who have passed us in some of the ratings include Australia, Norway, Sweden, Denmark, and Switzerland. These are are very successful countries.