INDIANAPOLIS -- The cost of auto insurance in Indiana is lower than most states, according to a study by the National Association of Insurance Commissioners.

Indiana ranked seventh nationally, improving from 10th last year.

The state's average annual premium dipped to $725, down about $30 from last year.

The national average is $936 annually. The study collected data from state insurance departments.

"Indiana consumers are fortunate to have a very healthy insurance market, and that competition helps to foster lower rates for Hoosiers," said Indiana Department of Insurance Commissioner Jim Atterholt.

Washington, D.C. was the most expensive in the nation for auto insurance premiums, with an average cost of $1,315 each year. Iowa was the cheapest, with an annual average of $644.