New data that was published recently shows a significant increase in mobile data usage (per subscriber), with higher growth by the top users.
Don Kellogg, Senior Manager, Telecom Research & Insights, Nielsen provides a more granular view of the distribution of data usage among smartphone users:
"mobile Data Tsunami initially described here is still growing at an astounding pace In just the last 12 months, the amount of data the average smartphone user consumes per month has grown by 89 percent from 230 Megabytes (MB) in Q1 2010 to 435 MB in Q1 2011. A look at the distribution of data consumption is even more shocking: data usage for the top 10 percent of smartphone users (90th percentile) is up 109 percent while the top 1 percent (99th percentile) has grown their usage by an astonishing 155 percent from 1.8GB in Q1 2010 to over 4.6GB in Q1 2011 .. Even as data usage has almost doubled, most users are paying around what they did a year ago for data. That translates to a lower cost per unit of data consumed. The amount the average smartphone user pays per unit of data has dropped by nearly 50 percent in the last year, from 14 cents per megabyte (MB) to a mere 8 cents".
See "Average U.S. Smartphone Data Usage Up 89% as Cost per MB Goes Down 46%" - here.