Here the population of each country is divided into 20 equally-sized income groups, ranked by their household per-capita income. These are called “ventiles,” as you can see on the horizontal axis, and each “ventile” translates to a cluster of five percentiles.
The household income numbers are all converted into international dollars adjusted for equal purchasing power, since the cost of goods varies from country to country. In other words, the chart adjusts for the cost of living in different countries, so we are looking at consistent living standards worldwide.
Now on the vertical axis, you can see where any given ventile from any country falls when compared to the entire population of the world.
Via: [NDTV Profit]