Apple has just five retail stores in mainland China, but revenue has increased exponentially every year, highlighting the potential for the iPhone, and all things Apple, in the world's most populous nation. In 2009, China accounted for just 2% of Apple's revenue, growing to 12% in 2010. Overall, the Asia-Pacific region accounted for 19% of Apple's total sales in the first quarter of fiscal 2012, up from 17% in the prior year's quarter. Demand for Apple products has become so intense in China that the company recently had to suspend selling the iPhone 4S at a China Unicom store due to the enormous amount of customers outside. While some believe the episode could have been better handled by Apple, the iPhone maker has undoubtedly become a victim of its own success. This much is certain. Apple is starting to take advantage of China's enormous potential, selling the iPhone every way it can. Shareholders are extremely pleased with the results, with shares up 24% year-to-date, and 43.2% year-over-year. Apple shares are up more than 2% in Tuesday trading to $512.72. -- Written by Chris Ciaccia in New YorkFollow TheStreet Tech on your wireless devices.