States where marijuana is legal

Jenny Cheng/Business Insider

• Recreational marijuana is legal in nine states and medical marijuana is legal in 30 states.
• A 2017 Gallup poll showed that 64% of Americans support legalization.
• Oklahoma became the 30th state to legalize medical marijuana on Wednesday. 

Oklahoma became the 30th state to legalize medical marijuana on Wednesday. Residents voted 56-43% in support of the ballot initiative, which is one of the most permissive medical marijuana laws in the US. 

Nine states and Washington, DC, have legalized marijuana for recreational use — no doctor’s letter required — for adults over the age of 21. 

In January, Vermont became the first state to legalize marijuana through the legislature, rather than a ballot initiative, when the governor signed the bill into law.

Marijuana prohibition began 80 years ago when the federal government put a ban on the sale, cultivation, and use of the cannabis plant. It remains illegal on the federal level.

Despite the efforts of Attorney General Jeff Sessions, who has been on a crusade to stamp out legal marijuana since his appointment, the industry is exploding.

Legal marijuana sales exploded to $9.7 billion in North America in 2017, according to a report from Arcview Market Research and BDS Analytics. That represents a 33% increase over 2016, shattering previous expectations about how quickly the marijuana industry could grow in the face of federal prohibition.

The report also predicted the legal marijuana market will reach $24.5 billion in sales — a 28% annual compound growth rate — by 2021, as more state-legal markets come online.

Support for marijuana legalization reached new highs in 2017. A Gallup poll showed that 64% of Americans favor legalization, and a majority of Republicans back it for the first time.