Apple sold its billionth iPhone last week.
"We never set out to make the most, but we've always set out to make the best products that make a difference," Cook said in a statement.
The record marks the latest accomplishment for the Cupertino, California, company, whose big bet on the device's success nine years ago remade the technology industry and turned Apple into the world's most highly valued company. The revenue of some of the globe's largest firms is now based on apps designed for the iPhone -- and for the rival devices that run Google's Android software.
How Apple will get to the next billion is still unclear. The company may finally have found a limit to iPhone sales increases. However, if rumors of a massively revamped device for next year are true, that could drive growth again.
Meanwhile, Apple on Tuesday reported its second consecutive quarterly decline in iPhone sales. Until the quarter that ended in April, iPhone unit sales had never dropped in the history of the device.
This article originally appeared on CNET.com.