"• Workers with a college education had a lower prevalence of current illicit drug use compared with those without a college education. The prevalence of past month use of illicit drugs was lower among those with higher levels of education than those with less education (college graduate [5.7 percent] vs. less than high school [11.2 percent]) (Figure 2.6 and Table 2.3).
"• The prevalence of current illicit drug use was lower among workers with higher family incomes than among workers with lower family incomes. An estimated 13.2 percent of workers who reported family income that was less than $20,000 had used illicit drugs during the past month. In contrast, 6.0 percent of workers who reported income in the highest category––$75,000 or more––had used illicit drugs during the past month (Figure 2.7 and Table 2.3).
"• Residents of noncore counties had a lower prevalence of current illicit drug use (4.5 to 6.2 percent) compared with residents of micropolitan statistical area (7.1 percent), small metropolitan statistical area (MSA; 8.8 percent), and large MSA (8.3 percent) counties (Table 2.3)."

Source

Larson, S. L., Eyerman, J., Foster, M. S., & Gfroerer, J. C. (2007). Worker Substance Use and Workplace Policies and Programs (DHHS Publication No. SMA 07-4273, Analytic Series A-29). Rockville, MD: Substance Abuse and Mental Health Services Administration, Office of Applied Studies, pp. 12-15.
http://adaiclearinghouse.org/…