Teen Mobile Phone Use in Japan
The Daily Yomiuri has another blurb citing a MHLW study. According to this one, 92 percent of high schoolers, 48 percent of middle school students, and 24 percent of fifth and sixth graders have mobile phones. A prior survey in 2001 found 27 percent and 9 percent for the latter two categories, but the blurb in the paper doesn't say about high school students.
It also says that more than 30 percent of high schoolers use their keitai (mobile phone) more than two hours a day. I suspect this includes voice, email, i-mode browsing and games, all rolled together.
This report ought to be on MHLW's news page (in Japanese), but I'm not seeing it; it may be rolled into another report...