The supply of cocaine fluctuated during the year, while cocaine abuse, the average purities of cocaine, and the amount seized in the United States declined. The decline in seizures is attributed to effective multinational law enforcement efforts that prevented major shipments from reaching the United States and to the increasing amounts of cocaine being sent to Europe. The heroin market is characterized by the prevalence of Southeast Asian heroin of high purity in the eastern United States and trafficking in Mexican heroin in the southwest and west. Marijuana remained the most commonly used illicit drug in the United States in 1990, but its use has declined in recent years. Other drugs that were the focus of enforcement efforts included d-methamphetamine hydrochloride (ice), LSD, benzodiazepines, and other drugs. Law enforcement efforts have also focused on seizures of drug-related assets. Figures and tables