Almost a third (31 percent) of all mobile phone users in the United States own smartphones, but their adoption is higher among specific minority groups, says a report out today from Nielsen.

Based on a survey conducted in December, Nielsen found that 27 percent of white mobile phone users in the U.S. currently own smartphones. But that rate was lower than the 45 percent of Hispanics, 45 percent of Asians/Pacific Islanders, and 33 percent of African-American mobile users polled who said they have a smartphone.

The adoption rates for smartphone ownership are also rising, especially among minority groups. Over the past six months, 42 percent of white users who bought a mobile phone opted for a smartphone, while 60 percent of Asians/Pacific Islanders, 56 percent of Hispanics, and 44 of African Americans made the same choice.

Which mobile platforms are proving the most popular

Among those who currently own a smartphone, Nielsen discovered a three-way tie among Research In Motion's BlackBerry, Apple's iOS, and Google's Android. However, ownership of a BlackBerry has dropped around 10 percentage points over the course of a year and iOS has remained the same, but Android has shot up 25 percentage points.

Further, more people who picked up a smartphone in the past six months went for an Android device, with 43 percent ownership compared with 26 percent for Apple's iOS and 20 percent for BlackBerry.

A report out yesterday from research firm Canalys noted similar trends in worldwide smartphone ownership, with Android surging to become the top smartphone platform across the globe.

Finally, Nielsen found that the iPhone was the top choice among Asians/Pacific Islanders, Hispanics, and white users. But among African-American smartphone owners, the BlackBerry pulled into the lead, owned by 31 percent of those polled.

Nielsen surveyed a total of 56,719 people to obtain the data on current smartphone ownership and 13,258 of them to get the stats on those who bought a smartphone over the past six months.