[USA] Substate estimates from the 2006 NSDUH / SAMHSA Office of Applied Studies, 19 June 2008
http://oas.samhsa.gov/substate2k8/SecA.htm#A.1
"This report presents estimates of the prevalence of substance use or mental health problems in substate regions based on data from the combined 2004-2006 National Surveys on Drug Use and Health."