Smartphone installed base: RIM 30% and fading, iPhone 28%, Android 19%

Source: Neilsen Co.

According to Nielsen's latest Mobile Report, issued Monday, Apple (AAPL) has nearly caught up to Research in Motion (RIMM) in the U.S. smartphone market, with 28% and 30% of installed base, respectively. Google's (GOOG) Android, with 19% is gaining fast.

"Among those who chose a device in the last six months," Nielsen reports, "Android took the lead in Q3, while RIM Blackberry and Apple iPhone are practically tied for second place."

See also:

• Canalys: Apple grabbed 26% of the U.S. smartphone market in Q3

[Follow Philip Elmer-DeWitt on Twitter @philiped]