NPD: Verizon iPhone users consume 1.58 GB/month, almost double those of Sprint

New data from NPD Connected Intelligence shows that Verizon Wireless' iPhone users are the most prolific data downloaders among the nation's top four wireless carriers.

The firm found that the iPhone customers of Verizon used an average of 1.58 GB of cellular data per month in September. The findings are noteworthy considering Verizon charges users on a per-MB basis, while rival Sprint Nextel has heavily advertised the fact that its iPhone plans offer unlimited data access. "Unlimit your iPhone," proclaims Sprint on its website. "No metering. No throttling. No overages." According to NPD's findings, AT&T Mobility iPhone users consume an average of 1.35 GB per month, putting the carrier into the No. 2 place. Sprint iPhone users are in the No. 3 position, downloading an average of 0.72 GB per month. T-Mobile USA's iPhone users consume an average of 0.19 GB per month, according to NPD. NPD's figures represent data usage across cellular networks and do not include Wi-Fi data usage. Smartphone customers typically transmit 2 to 3 times more data over Wi-Fi than cellular. The bulk of AT&T's iPhone users are likely on the carrier's HSPA network. The bulk of Verizon and Sprint's iPhone users are likely on the carriers' CDMA EV-DO networks. And the bulk of T-Mobile's iPhone users are likely on the carrier's EDGE network.