Xr13-103 Has the illicit use of drugs decreased over the past 10 years? Government agencies have undertaken surveys of Americans 12 years of age and older. Each was asked whether he or she used drugs at least once in the previous month. The results of this year’s survey and the results of the survey completed 10 years ago were recorded as 1  no and 2  yes. Can we infer that the use of illicit drugs in the United States has increased in the past decade? (Adapted from the U.S. Substance Abuse and Mental Health Services Administration, National Household Survey on Drug Abuse.)