Table 3. Estimated Number of Chronic and Occasional Users of Cocaine and Heroin, 1988�2000 (Thousands)

Year	Cocaine users		Heroin users
	Occasional1	Chronic2	Occasional1	Chronic2
1988	6,000	3,984	170	1,341
1989	5,300	3,824	150	1,266
1990	4,600	3,558	140	1,119
1991	4,478	3,379	359	1,015
1992	3,503	3,269	304	955
1993	3,332	3,081	230	945
1994	2,930	3,032	281	932
1995	3,082	2,866	428	923
1996	3,425	2,828	455	910
1997	3,487	2,847	597	904
1998	3,216	2,800	253	901
1999	3,216	2,755	253	898
2000*	3,035	2,707	253	898

Note: Data in this table are preliminary composite estimates derived from the National Household Survey on Drug Abuse (NHSDA) and the Arrestee Drug Abuse Monitoring (ADAM) program (see W. Rhodes "Synthetic Estimation Applied to the Prevalence of Drug Use," Journal of Drug Issues 23(2):297�321, 1993, for a detailed description of the methodology). The NHSDA was not administered in 1989. Estimates for 1989 are the average for 1988 and 1990.

*Estimates for 2000 are projections.
¹ "Occasional" is defined as using drugs fewer than 10 days per month.
² "Chronic" is defined as more than 10 days per month.