Found on What Japan Thinks, japan.internet.com and JR Tokai Express Research recently conducted a survey to find out about “meiwaku” mail (spam). They interviewed 330 mobile-phone owners, 60 percent male, from all around the country by means of an internet-based survey. 19.9 percent of respondents received at least 1 spam mail per day.
They interviewed 330 mobile phone owners, 60% male, from all around the country by means of an internet-based survey. The sample consisted of 25.2% in the their twenties, 43.0% in their thirties, 21.5% in their forties, 7.6% in their fifties, and 2.7% in their sixties. Full report here.