PwC has confirmed its intention to invest $100 million in Africa over the next three years, Reuters has reported.Speaking at a news conference in Kenya, Dennis Nally, chairman of PwC International, explained that that the expansion plan was in response to foreign firms demanding more African coverage.He also said that it will mean doubling PwC's nearly 8,000 African staff over five years."We are getting a clear signal from our international clients that Africa is an increasingly important market," he commented."Africa is an important frontier for economic growth. We believe the regional economy could double by 2020 to nearly $3 trillion."Although PwC already has a presence in 31 of Africa's 54 countries, the accountancy firm wants to broaden that into states at the far end of the "frontier market" spectrum."We want to deepen our presence in those countries and open additional offices in places that have become conducive to our business," said PwC regional head Philip Kinisu.