Of all the places, I finally found the table on gizmag.
Go here to for more details on how these were selected and ranked.
Puzzling, isn't it?
18. Ecstasy (MDMA)
Further reading on ABC classification systems, Schedule I through V defined, and summary of drug legislations between US, UK, Netherlands, Sweden: http://www.publications.parliament.uk/pa/cm200506/cmselect/cmsctech/1031/103105.htm#a1