ECPATの国別レポート 2nd Edition(2011年) P9 http://www.ecpat.net/sites/default/files/a4a_v2_eap_japan.pdf
Statistics on the number of children involved in enjo kosai are hard to find. However, some estimates have put the number of school-aged girls practicing enjo kosai at about 13%. A Tokyo survey by Friday magazine reportedly found that 75% of schoolgirls claimed that older men seeking an enjo kosai relationship had solicited them.*1
ECPATの国別レポート 2nd Editionに引用されたAsia Timesの記事(2008年) http://www.atimes.com/atimes/Japan/JE10Dh01.html
Also, another problem with the enjo kosai industry is that the number of prospective punters far outnumbers the amount of willing schoolgirls. Some estimates have put the number of school-aged girls practicing enjo kosai at about 13%, and a Tokyo survey by Friday magazine found that an astonishing 75% of schoolgirls reported that they had been solicited by older seeking an enjo kosai relationship.
The moral problem is partially one of clients outnumbering willing kogals.While even the most liberal estimates limit enjo kosai to 13 percent of school-aged girls, a Tokyo survey found that an amazing 75 percent of girls responding had been solicited by older men interested in enjo kosai.