Even though worldwide wealth is increasing — it rose more than 3% to $80.68 trillion in 2017 — not all of the regions are experiencing the same level of affluence. North America has less than than 5% of the global population, yet the region accounts for about one-fourth of global gross domestic product. On the other hand, nearly 25% of the world’s population lives in South Asia, but the region’s economic activity accounts for less than 4% of global GDP.

GDP may be the standard method for gauging the size of a particular country or region’s economy, but it does not account for all of the wealth generated by that nation. A more accurate indicator of a country’s economic output is its gross national income, or GNI. This measure captures all economic activity within a nation’s borders in addition to wealth created by nationally owned entities that operate in other countries.

Using data from the World Bank, 24/7 Wall St. reviewed the GNI per capita of about 180 nations to identify the 25 poorest countries. We also included life expectancy at birth from the World Bank, as well as GDP from the International Monetary Fund (IMF).

The world’s poorest countries share some characteristics that may contribute to their impoverished state. All but three of the countries on this list are located in sub-Saharan Africa. Many of these countries are landlocked and are mostly characterized by agriculturally based economies that struggle with the effects of desertification. Many of the nations on the list are rich in resources and susceptible to boom-and-bust economic cycles. Resources-based economies can also be among the most corrupt. Conditions in the world’s most impoverished countries are reflected in their life expectancies. No nation on this list has a life expectancy at birth that exceeds the global average of 72.0 years

Click here to see the 25 poorest countries in the world.