This is a link to the 4th annual report from the Rocky Mountain High Intensity Drug Trafficking Area publication which reports on the effects of legalization in Colorado.
Colorado youths who use marijuana was 70% higher than the national average
College-age marijuana use was 62% higher than the national average
Adult marijuana use increased 63% since legalization
Colorado youth, college-age young adults, and Colorado adults all ranked number one in the nation for past month marijuana use
Emergency department marijuana visits increased 49% after legalization
Hospitalizations related to marijuana nearly doubled from 6,305 in 2011 to 11,439 in 2014