One of the more controversial social and political issues affecting the country is the legalization of medical and recreational marijuana. A Gallup Poll released in October 2015 shows 58 percent of American adults think that marijuana should be legal, up from 51 percent a year ago. The U.S. market for legal cannabis grew 74 percent in 2014 to $2.7 billion, up from $1.5 billion in 2013. Public perception of the medicinal and recreational use of the drug has changed over the last decade as 23 states and the District of Columbia have now approved the lawful use of marijuana for certain medical purposes, either by statute or ballot measure.