STUDIO CITY (CBSLA) — A report out Thursday finds marijuana use among adults increased by over a third in the years leading up to the passage of California’s recreational cannabis law.

The report from the Los Angeles County Dept. of Public Health found the percentage of adults over the age of 18 who reported using marijuana increased 33 percent from 2011 to 2015, from 9 percent to 12 percent.

Results of the 8,008-adult survey indicated a person’s country of origin was a factor in whether or not they used marijuana. As an example, researchers pointed to the fact that use among Latinos and Asians overall, 10 percent and 6 percent, respectively, was lower than whites at 15 percent. However, use among U.S.-born Latinos and Asians was much higher. For U.S.-born Latinos it was 20 percent; U.S.-born Asians used more than double at 13 percent.

“The extremely low use of marijuana among those not born in the US is encouraging and suggests that cultural norms may have a protective effect in immigrant communities,” researchers concluded.

Twenty percent of African-Americans surveyed said they used marijuana.

They also noted use among adults living below the federal poverty lever was lower than all other income groups at 8 percent, while use among U.S.-born persons living under the poverty line was 19 percent.

“High rates of marijuana use among low-income communities prior to the passage of Prop 64 means we must pay close attention to where dispensaries are clustered post-legalization,” researchers said.

Proposition 64, passed in 2016, allowed adults 21 and over to possess up to an ounce of marijuana. Purchases of cannabis at licensed dispensaries was made legal this year.