A choropleth map of World Bank Dataset: GDP per capita, PPP (current international $).

See also:

• Wikipedia: List of countries by GDP (PPP)
• World Bank: GDP per capita, PPP (current international $)
• GitHub Gist: World Bank Dataset: GDP per capita, PPP (current international $)
• MDN: String.prototype.substring()
• MDN: Promise.all
• MDN: Map
• d3.scaleQuantile
• Wikipedia: Quantile
• d3-scale-chromatic
• ColorBrewer