for additional confounders such as peer drug use, found that cannabis use and associations with later hard drug use existed only for non-identical twins. The study suggested that a causal role of cannabis use in later hard drug usage is minimal, if it exists at all, and that cannabis use and hard drug use share the same influencing factors such as genetics and environment. Health Health arguments for drug laws Advocates of prohibition argue that particular drugs should be illegal because they are harmful. Drug Free Australia for example argues "That illicit drugs are inherently harmful substances is attested by the very nomenclature of the 'harm reduction' movement." The U.S. government has argued that illegal drugs are "far more deadly than alcohol" saying "although alcohol is used by seven times as many people as drugs, the number of deaths induced by those substances is not far apart. According to the Centers for Disease Control and Prevention (CDC), during 2000, there were 15,852 drug-induced deaths; only slightly less than the 18,539 alcohol-induced deaths." Ratios of the harms of illicit opiates to licit alcohol and tobacco in Australia are similar, with 2 deaths per hundred opiate users per annum versus 0.22 deaths per hundred for alcohol (9 times less) per year and 0.3 for tobacco (7 times less). The DEA has said: Many of the deaths from using cannabis, other than from car accidents while intoxicated or violence and aggression, are more likely to figure in the longer term, just as with tobacco, where both nicotine overdose and cannabis overdose are extremely rare or nonexistent. While ecstasy may have lower rates of immediate mortality than some other illicits, there is a growing science on the already recognized considerable health harms of ecstasy. Drug Free Australia argues that distinctions between "soft" and "hard" drugs are entirely artificial, and titling cannabis "soft" or ecstasy "recreational" does not lessen the extensive harms of these substances. Gil Kerlikowske, former director of the US Office of National Drug Control Policy (ONDCP) argues that in the United States, illegal drugs already cost $180 billion a year in health care, lost productivity, crime, and other expenditures, and that number would only increase under legalization because of increased use. Drug Free Australia claims arguments that increased health harms of illicit drugs are the result of lack of government regulation of their purity and strength are not well supported by evidence.