"In 2011, 9 percent of all substance treatment facilities had OTPs (Figure 1). This percentage has consistently been between 8 and 9 percent since 2001, when the Substance Abuse and Mental Health Services Administration began certifying OTPs. While the number of facilities with OTPs has remained constant at around 1,100 to 1,200 since 2003, the number of clients receiving methadone on the survey reference date5 increased from about 227,000 in 2003 to over 306,000 in 2011 (Figure 2). Clients receiving treatment with methadone accounted for approximately 21 to 25 percent of all substance abuse treatment clients each year. The increase in the number of clients receiving methadone treatment coupled with the stability of the proportion of clients receiving this treatment suggest that the overall availability of methadone treatment has increased over time."

Source

Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality. (April 23, 2013). The N-SSATS Report: Trends in the Use of Methadone and Buprenorphine at Substance Abuse Treatment Facilities: 2003 to 2011. Rockville, MD, p. 2.
http://www.samhsa.gov/data/2k…