Read this and answer the question. If the question is unanswerable, say "unanswerable".

According to CIA World Factbook, the people of Republic of the Congo are largely a mix of Catholics (33.1%), Awakening Lutherans (22.3%) and other Protestants (19.9%). Followers of Islam make up 1.6%, and this is primarily due to an influx of foreign workers into the urban centers.

Who form the majority of Islamic residents of the Congo?
foreign workers