Android further cemented its position as the most widely used smartphone operating system in the United States over the past three months according to new data just released by Nielsen. During the three-month period from August through October, Android’s market share ticked up to 44.2% from 43% between July and September. Apple’s iOS platform grew marginally from 28% to 28.6% and RIM’s BlackBerry OS shed three points to fall to 17%. Microsoft’s share is still barely a blip on the radar. Apple’s 28.6% kept it at the top of the vendor list over the past three months and HTC was still the No.2 vendor over all, followed by RIM and Samsung. Nielsen also noted that 44% of all mobile subscribers in the U.S. now own smartphones, and 56% of subscribers who purchased a cell phone in the past three months chose a smartphone. Finally, the market research firm says 71% of smartphone users in the U.S., and 83% of app downloaders, now own either an iPhone or Android smartphone.