The foreign-born population from Africa in the United States has approximately doubled every decade since 1970, according to a new report from the Census Bureau. The African-born population living in the U.S. grew from around 80,000 to around 1.6 million between 1970 and 2008-2012, according to the report.

African-born immigrants now represent 4 percent of the foreign-born population in the U.S., and much more in some states: Africans are 19 percent of immigrants in Minnesota and North Dakota, and 15 percent in Maryland. This chart shows the population’s explosive growth, though today, the group still represents just 0.5 percent of the U.S. population:

African-born people living in the U.S. outperformed the overall foreign-born population and the native U.S. population in terms of their level of education: Approximately 41 percent of the African-born population had a bachelor’s degree or more, compared with 28 percent of the total foreign-born population.

But educational attainment levels vary within the African-born population: 40 percent of Somali-born persons, for instance, had not obtained the equivalent of a high-school education (higher than the average for foreign-born U.S. residents), while 64 percent of Egyptian-born persons and 61 percent of Nigerians had a bachelor’s degree or more.