Black Americans were nearly four times as likely as whites to be arrested on marijuana-possession charges in 2010, even though the two groups used the drug at similar rates, say new federal data reported by the New York Times. The disparity had grown steadily from a decade before, and in some states, including Iowa, Minnesota and Illinois, blacks were eight times as likely to be arrested. During the same period, public attitudes toward marijuana softened and several states decriminalized its use. Half of all drug arrests in 2011 were on marijuana-related charges, roughly the same portion as in 2010. “We found that in virtually every county in the country, police have wasted taxpayer money enforcing marijuana laws in a racially biased manner,” said Ezekiel Edwards of the American Civil Liberties Union. During President Obama's first three years in office, the arrest rate for marijuana possession was about 5 percent higher than the average rate under President George W. Bush.