According to the TV program Ranking Kingdom who interviewed 300 girls in Shibuya the average Shibuya girl sends 10.5 e-mails per day on her cell phone.

It's easy to believe too. I watched a girl on the train easily typing 15 or 20 words a minute on her cell phone. I'm sure she was not looking at the keys but just at the screen and she also new all the menus so well they just flew by.