Industry analyst Horace Dediu from Asymco wanted to try to figure out what percentage of the U.S. smartphone market the Apple iPhone will have captured when it peaks. The peak will probably take place when everyone who wants an iPhone has purchased one. Replacement sales will be leading the way and the number of new iPhone buyers will be growing more slowly.
Using a mathematical formula that we can't even pretend to understand, Dediu computes that the Apple iPhone will reach 90% penetration of the U.S.market (which is considered saturation) when 68% of the U.S. population sports one. The analyst sees this taking place in February 2017, so be prepared. At that time, Dediu sees 180 million Americans with an iPhone in their pocket or purse.
source: Asymco via Forbes