New York:  Many thought this race would be determined by the end of 2010, but as we roll into 2011 the mobile phone race is still too close to call.

According to a report released Monday by Nielsen, the market research company, Apple’s iPhone operating system is still the top mobile OS in the United States, controlling 28.6 percent of the smartphone market. Google’s Android platform is close by at 25.8 percent of the market, rising steadily as it nips at Apple’s heels.

The BlackBerry from Research In Motion, once the leader in the smartphone space, continues on its steady decline and now controls 26.1 percent of the market. In June 2010, Research In Motion was far ahead of Apple and Google with a 33 precent share.

Nielsen noted in the report that the race to own the “consumer market share is tighter than it has ever been” since the smartphone emerged as a multibillion-dollar market several years ago.

Earlier mobile reports by Nielsen noted that the smartphone market would not stabilize in the near future, as Apple, Google and RIM continued to add customers to the smartphone ranks. The latest numbers from Nielsen show that during November, 45 percent of mobile phone customers decided to buy a smartphone over a feature phone.