The U.S. Department of Energy (DOE) says that the state of California had the highest concentration of plug-in vehicles (PEVs) relative to population in 2015, with 4.68 PEVs per 1,000 people. In comparison, there were only five U.S. states total with more than two PEVs registered per 1,000 people.
According to the DOE, Hawaii had the second-highest concentration, with nearly three PEVs per 1,000 people – followed by Washington, Georgia and Oregon with about two PEVs per 1,000 people.
The DOE adds that Georgia is the only eastern state with over two PEVs per 1,000 people, likely due to generous state incentives that were offered until summer 2015. Mississippi had the lowest concentration of PEVs, but all 50 states and the District of Columbia reported at least one PEV.