The use of mobile phones is booming in Africa, where subscriber-growth rates exceeded 100% in some countries last year, according to Informa, a research group. Markets in the extreme north and south of the continent are the most mature, and growth rates are healthy in much of sub-Saharan Africa. Trailing the field are Eritrea and Ethiopia, where state telecoms monopolies prevail.
Source: http://economist.com/markets/indicators/index_wide.cfm?page=Emerging%20Market&story_id=5471737
Other emerging market indicators:
