For a device that represents about 0.4% of the mobile handset market, the iPhone generates an awful lot of Internet traffic.

How much, you ask?

“Unheard of levels,” according an executive at O2, which on Monday announced plans to deploy a network of bandwidth boosting femtocells across the U.K. to handle the extra load. (see here)

And yesterday at the Mobile World Congress in Barcelona, a Google GOOG executive offered a more precise measure. According to Vic Gundotra, head of the company’s mobile operations, Google is seeing 50 times more searches from Apple AAPL iPhones than from any other mobile handset.

“We thought it was a mistake and made our engineers check the logs again,” he told the
Financial Times
.

The FT notes that Google’s findings dovetail with earlier reports. In December, O2 reported that more than 60% of iPhone users use over 25mb/month of data, while only 1.8% of O2’s non-iPhone customers go over that mark.