Dediu arrived at the above figure by looking at the past performances of the iPhone on the other three major networks -AT&T, Verizon and Sprint.
“From the initial product launch until the end of 2012, AT&T has activated 72 million iPhones,” Dediu writes for AYSMCO. “Verizon began selling iPhones four years after AT&T and managed to activate 26 million since. Sprint began nine months after Verizon and has activated 8.5 million.”
Dediu:[quote] I identified the reported iPhone activations with blue areas while the sum of green and blue areas represents total subs at the end of the given year.
I also took the liberty of forecasting 2013 data in order to try to estimate T-Mobile’s contribution.
The method used was to look at the percent of total subs that each operator has been activated. Accounting for the limited sales period for Sprint in 2011, the sales patterns are consistent across the carriers. The longer the product is available, the higher the activation rate.[/quote]
Based on these data, Dediu, “estimated that in 2013 T-Mobile USA will sell about 10% of its subs base on iPhone. That would make its contribution to iPhone sales about 3.4 million.”