Africa Has More Mobile Phones than U.S.: In fact, the continent has more mobile phones than all of North America and Europe. Asia is the only place in the world with more mobile phones than Africa. There are currently 650 million subscribers in Africa, according to the World Bank. The market has grown 40-fold since 2000.
It shouldn't be a big surprise that they've boomed in popularity over the last decade or so. Landlines are expensive because they require a wired infrastructure; cellphones only require towers.
Having access to a cellular network seems to directly affect personal economic growth.