Foreign Fighters in African Islamist Insurgencies: Diverse Origins and Growing Numbers (warontherocks.com)

• 53% of IS-Somalia fighters are foreign
• 33% for IS-West Africa and IS-Sahel
• Growth slower than 2020 forecast

"A follow-up analysis six years after a 2020 prediction finds that foreign fighter numbers in African Islamist groups have increased, but more gradually than expected. Estimates show 53% of IS-Somalia, 33% of IS-West Africa, and 33% of IS-Sahel are foreign fighters, including Americans."