From the 2012 SAMHSA National Survey on Drug Use and Health:

“Among adults aged 18 or older, the rate of current illicit drug use was higher for those who were unemployed (18.1 percent) than for those who were employed full time (8.9 percent), employed part time (12.5 percent), or “other” (6.3 percent) (which includes students, persons keeping house or caring for children full time, retired or disabled persons, or other persons not in the labor force) …. The percentage of adults employed full time who were current illicit drug users increased between 2011 (8.0 percent) and 2012 (8.9 percent).”

Read it here.