Android is continuing dominance in the U.S. mobile market with 45 percent of all smartphones nationwide according to Internet marketing research company comScore. Android closed out the third quarter with just shy of 45% percent market share, up nearly 5% percentage points since June 2011. The only company with positive growth or any improvement for the same time frame was Apple’s iOS, which garnered 0.8 percentage points over June gaining 27.4 percent of the U.S. smartphone pie.

It really is no surprise to most, especially since Nielsen’s research study basically mirrored the same results. The more interesting point is how the gains in both Android and iOS coordinated with declines in the market share of RIM, Windows Mobile and Symbian. RIM just continues to languish, with a nearly 5% decline, floundering underneath 20% percent. Lastly, Microsoft fell 0.2 points to 5.6 percent and Symbian now commands 1.8 percent, down 0.2 percent since June. With so many devices on offer for Android it’s no surprise it is dominating day after day. Google’s OS is saturating the market with mid- to high-end handsets and this is hard to compete against, no matter who you are, even Apple.

Besides market share, the comScore survey also provided some details on mobile content usage. Text messaging was the most common activity, claiming 71.1% of respondents, while browser usage sat at 42.9%, app downloading at 42.5%, social networking at 31.5%, game-playing 28.8%, and music listening at 20.9%.