Several economies that are not considered to be sovereign states (i.e. autonomies and dependencies) are included because they appear in the sources.The figures are based on World Bank data (2015 with some exceptions), and Wikipedia statistics - GDP (PPP) per capita Int$;
Autonomy = Island having right or condition of self-government
Three hints: 1) The GDP per capita (PPP) 2) Mother country if the island is not a sovereign independent nation, and 3) Population in millions;