Smartphones with 4G connectivity grew from 6% in the fourth quarter of 2010 to 35% in the fourth quarter of 2011, according to a report from The NPD Group. HSPA+ “4G” accounted for 22% sales, however, leaving LTE and WiMAX technologies with a much less impressive share of the smartphone market. Older HSPA+ technology was the only 4G offered by AT&T up until recently, and it is still the only 4G technology offered by T-Mobile. The firm also counts AT&T’s iPhone 4S among the 4G phones sold last quarter, giving the category a significant boost. LTE-enabled handsets, on the other hand, accounted for just 7% of the smartphone market, while WiMAX made up only 6%, dropping from its third-quarter high of 10%. Verizon’s HTC Thunderbolt was the most popular LTE handset in the fourth quarter last year, while Sprint’s HTC EVO was the most popular WiMAX device. Read on for NPD’s press release.