Table 1 Description of Data Sources Utilized to Calculate Drug Treatment Coverage Rates

1) Proportion of treatment entrants who indicated that they injected substances intravenously in each MSA and year (1993–2007) as reported by the Treatment Episode Data Set (TEDS) [58];

2) Total number of drug users in drug treatment as of October 1 of each year reported by the Uniform Facility Data Set (UFDS) for 1993, 1995, 1996–1998 [59, 60] and the National Survey of Substance Abuse Treatment Services (NSSATS) for 2000, 2002–2007 [61];

3) Total estimated number of PWID in each MSA and year (1993–2007) as calculated and reported by Tempalski and colleagues [62].