Nielsen Mobile Insights' latest statistics are in -- and would you look at that. It's the rise of smartphone owners crossing paths with the decline of those still clinging to their feature-focused devices. According to its latest Smartphone Penetration report, as of February 2012, 49.7 percent of US mobile phone owners now sport the "smarter" types (up from only 36 percent a year ago). On a unsurprising note, Nielsen also found that two-thirds of mobile phone buyers in the last three months purchased smartphones over dumbphones. According to its latest report on Smartphone OS shares, of those smartphone purchases, 48 percent of buyers went with Android, 43 percent landed iOS a close second and five percent helped RIM scrape the bottom of the barrel with the remaining four percent listed as "other." That said, it's a only slight deviation from January's numbers, when 51.7 percent of folks went with Android, while 37 percent went for the route leading to Apple. Don't take our word for it, though, there's another graph past the break and full details at the source link below.