Apple’s iPhone is continues gain popularity in the United States, according to a new research report published by Canaccord. The report also suggests that Research In Motion’s market share in the United States is still sliding. “Our February checks indicated that iPhone sales remained strong in the U.S. and that sell-through of the iPhone led to additional market share gains versus its competitors,” Canaccord’s Mike Walkley said. He expects Apple to sell 32.6 million iPhone devices this quarter, representing a 23.7% market share, Barron’s said. Samsung’s could have a 24.3% market share with 33.5 million units sold, too, propelled by the success of its Galaxy S II devices. RIM’s share is expected to shrink to 8%, followed by Windows Phone with a 7.1% market share. “While Curve 9360 sales are likely to remain weak given our expectations for more affordable Curve 9320 products shipping in upcoming months, the weak Bold 9900 sales lead us to believe Street estimates remain too high for RIM’s F2013,” Walkley said in his report.