Members of the SACU:
Southern African Customs Union
The SACU is a trade agreement of currently 5 countries in Southern Africa.
All member states comprise a total area of 2.67 million km² and about 67.50 million people. This is 1.77% of the habitable area around the world and 0.87% of the world population. With an economic output of 366.97 billion US dollars annually, they represent around 0.43 percent of the global economy. The value of all exported goods of these 5 countries was 105.24 billion US dollars per year at last count.
Official website: https://www.sacu.int/