With the smartphone market growing fast, an analyst is suggesting Apple could be selling 50 million iPhones per annum by 2011.

In its 2009 fiscal year, Apple is estimated to have sold 20 million iPhones.

According to Barron's, Bernstein Research analyst Toni Sacconaghi says Apple can increase sales as it widens its distribution in North America and Europe, and launches in China.

Sacconaghi suggests breaking AT&T's exclusivity in the US and partnering with Verizon would add 11 million sales per year, while Europe could add a further 3.5 million units. Depending on its chosen distribution, the Chinese market could rank at between 2.9 to 6 million units per year.

Mike Abramsky, an analyst with RBC Capital Markets, goes even further. According to Apple Insider, he suggests iPhone shipments will be around 82 million unit by 2012.

This would give Apple 16 percent of the smartphone market, up from around 1 percent today.

Of course, this would depend on Apple continuing to fragment its family of devices in terms of functionality, price and contracts; something that's particularly important for the majority pre-paid and non-data plan mobile users.