The most recent of these studies from IIHS shows that injury and fatal crash rates in California, Colorado, Nevada, Oregon and Washington jumped in the months following the relaxation of marijuana laws in each state. Combined, the impact of legalization and, subsequently, retail sales in the five states resulted in a 6% increase in injury crash rates and a 4% increase in fatal crash rates compared with other Western states where recreational marijuana use was illegal during the study period. Only the increase in injury crash rates was statistically significant.