AT&T and Sprint both report falling iPhone sales percentages in Q1 2013

Apple’s cheer at the generally positive market reaction to its quarterly report may be somewhat muted by the news that iPhone sales fell at both AT&T and Sprint.

AT&T’s Q1 results revealed sales of 4m iPhones, or 67% of all its smartphone sales. This is down from 84% in the final quarter of 2012 which is of course the holiday quarter where people give and receive gifts…