Middle-income countries, as defined today, accounted for less than a fifth of the global economy (17 percent) even at the beginning of the 20th century. However, by 2017, their share had doubled to 35 percent.
The share for lower middle income countries doubled from 4 percent in 2002 to 8 percent in 2017 while the share for upper middle income countries increased from 13 to 27 percent. High-income countries, currently home to fewer than one in five of the world’s people, saw their share of global GDP fall from 83 percent to 64 percent. Economic growth in high-income countries remains below that of the rest of the world, so this share is likely to fall further. Low-income countries, which account for just nine percent of the world’s population, produce just over half a percent of global GDP.
The chart above classifies countries according to the FY19 income groups and applies these to previous years to compare the same set of countries.