U.S sales of Google's (GOOG) smartphone operating system dropped from 15.3 mil units in Q2 '11 to 13.4 mil in Q2 '12, according to researcher firm Strategy Analytics. Android now only controls 56% of the smartphone market. But Apple (AAPL) is gaining ground as its iPhone shipments in the quarter rose to 7.9 mil from 5.9 mil last year. Overall U.S. smartphone shipments were down 5% to 23.8 mil during the quarter. Google shares fell 0.4% to 632.30. Apple shares rose 1.7% to 595.03.