The use of recently released population projections based on the 1990 Census results in more accurate estimation, but causes some inconsistencies with 1992 and earlier estimates, which used 1980 Census-based projections. The effect is inconsequential for estimates of rates, but has a significant impact on certain estimates of the number of users, particularly for blacks and Hispanics. A full discussion of the impact of the shift to 1990 Census-based estimates is contained in Appendix 2. Tables and text utilize prevalence measures in terms of both the number of drug users and the rate of drug use in the population. Generally the analysis utilizes estimates of the number of users to describe changes in prevalence over time and rates to describe differences in use between population subgroups.
Tables also present data by population density.
Small metropolitan areas are MSAs with a population of less than 1 million. Non metropolitan areas are areas outside of MSAs. Data are also presented for four geographic regions. North Central - North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Louisiana, Missouri, Wisconsin, Illinois, Michigan, Indiana, Ohio. South - Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Tennessee, Kentucky, West Virginia, Virginia, Maryland, Delaware, District of Columbia, North Carolina, South Carolina, Georgia, Florida, Alabama.