During a conference call discussing its fiscal fourth quarter financial results, Apple announced that it had sold over 1.1 million iPhones during the three-month period, for a total of about 1.4 million since the June 29th launch. The company also estimated that about 250,000 of those devices were sold to people who did not intend to use them on the AT&T network, and instead sought to unlock the devices for use on other carriers. The estimation is apparently yielded by comparing the number of units shipped with the corresponding share of revenue received from AT&T subscription fees.
In fact, Apple said unlocking technology was a sales catalyst.
Appple COO Timothy Cook said "Some number of these (1.4 million iPhones) were sold to people who have an intention to unlock. While we don't know precisely how many people are doing that, our current guess is that there were probably 250,000 of the 1.4 million were sold to people with the intention of doing that (unlocking). Many of those (sales) happened after the price cut."