Sixty-nine percent of smartphones sold in the US run either Apple’s iOS or Google's Android platforms.

In the three-month period ending July 2011 Apple and Google both grew their US market share, pushing smartphone makers such as RIM and Microsoft further out of the picture.

According to figures from market researcher comScore, Google continued its run as the smartphone market leader adding 5.4 points to its April 2011 market share of 36.4 percent.

Apple’s market share grew too, albeit by a smaller 1 point to claim 27 percent of the market in July. BlackBerry maker Research In Motion (RIM) slipped from 25.7 percent to 21.7 percent, Microsoft dropped from 6.7 percent to 5.7 percent and Nokia’s Symbian platform dwindled from 2.3 percent to 1.9 percent of the market.

Smartphone ownership in the country is on the increase, making up 35 percent of the entire mobile market.

"82.2 million people in the U.S. owned smartphones during the three months ending in July 2011, up 10 percent from the preceding three month period," said comScore.

Samsung retained its position as the number one OEM across the entire mobile market in the US, capturing a 25.5 percent market share. LG, Motorola, Apple and RIM followed with market shares of 20.9 percent, 14.1 percent, 9.5 percent and 7.6 percent respectively.