Because that 14% of the worlds population is 96 million potential Iphone sales?
As of 1Q2010, there are 540+ million CDMA2000 subscribers around the world.
However, I would think Apple's primary target (if they did a CDMA iPhone) would be the 200 million current subscribers located in the Americas, especially the 164 million in North America alone.
Not to mention the couple of hundred million who aren't current subscribers, but could be potential leapers.