Google's Android mobile operating system may be surging, but it hasn't overtaken Apple's iOS in the U.S., according to a Nielsen report released today.

Using November data, market research firm Nielsen on Monday ranked Apple's iOS as the No. 1 mobile operating with 28.6 percent of the smartphone operating system market share in the U.S. Coming in at No. 3 is Google's Android with 25.8 percent share of the U.S. market.

What's really interesting is that RIM's BlackBerry operating system, which is the No. 2 ranked mobile operating system in the U.S. by market share with 26.1 percent, is within the margin of error of both Apple iOS and Android.

"In other words, RIM remains statistically tied with both Apple for first and Android for third," writes Nielsen. "Apple's clear lead over Android notwithstanding, this race might still be too close to call."

The popularity of Android is clear though. Among those consumers who purchased a smartphone in the last six months, 40 percent chose the Android OS.

Overall, 45 percent of consumers in November chose a smartphone over a regular cell phone, according to Nielsen.