The short answer, no. The long answer, it depends.
June 2010, Pieter Uys, Vodacom CEO confirmed that they had sold 90 000 iPhones. With the launch of the iPhone 4 on both Vodacom and MTN, I’m taking a guess that there are roughly 200 000 iPhones in SA. Take into account that not everyone that owns an iPhone has downloaded apps, the number of people that might actually then have access to your app is pretty low.