The graph below suggests that the New Mexico highway fatality rate is highly related to the U.S. fatality rate. Other aspects need to be considered, however. Among these are the lagged New Mexico rate and the lagged U.S. rate, and perhaps time itself. Whatever model is finally adopted, the residuals from the model should be independent of time (as indicated by some test such as the Durbin-Watson statistic). Use stepwise regression to sort out the variables significantly related to the New Mexico fatality rate, and indicate what a test of the serial residuals tells you.