Complex sentence: According to a 2012 survey, around half of the U.S.' mobile consumers own smartphones and could account for around 70% of all U.S. mobile devices by 2013; in the 25 to 34 age range, smartphone ownership is reported at 62%.
Split into simpler sentences: According to a 2012 survey, around half of U.S. mobile consumers own smartphones. They could account for around 70% of all U.S. mobile devices by 2013; in the 25 to 34 age group, smartphone ownership is so far reported at 62%.