(Telecompaper) T-Mobile US announced that it set a new record in quarterly customer additions in the fourth quarter of 2018, growing by 2.4 million to a total of 79.65 million customers at the end of the year. Over the full year, the customer base grew by 10 percent or just over 7 million customers. Branded postpaid net additions totaled 1.4 million in the quarter, taking the total annual growth to 4.5 million, better than the company's already improved guidance.