1974 45,196 1,280.54 3.53 213,853,928 21.134 decrease-17.14
When they made the speed limit to 55 in '74, deaths decrease by 17%.
And decrease since then even more and has never been that high again.
http://en.wikipedia.org/wiki/Motor_vehicle_fatality_rate_in_U.S._by_year#Motor_vehicle_deaths_in_U.S._by_year