Meraki installs wifi networks in many popular restaurants, such as McDonald's, Burger King and Starbucks. Recently, they released a report showing that mobile devices have overtaken computers as most-connected on restaurant wifi networks. Their networks reach about 40 million users in over 140 countries, so they have a far reach as far as gathering usage data goes (via CNNMoney).
They found that iPhones make up 32 percent of wifi connections on their networks. Windows OS is 23 percent, OS X is 13 percent, iPod touch makes up 11 percent, as does Android. The iPad is used by four percent and other devices make up six percent.
However, when it comes to data consumed by devices, they found that the iPad uses around 400 percent more data than the other devices (Android, iPhone and iPod touch combined). That's a lot of data.