Automobile ownership was rare in Sabresia as recently as 30 years ago, but with continuing growth of personal income there, automobile ownership has become steadily more common. Consequently, there are now far more automobiles on Sabresia' s roads than there were 30 years ago, and the annual number of automobile accidents has increased significantly. Yet the annual number of deaths and injuries resulting from automobile accidents has not increased significantly.
The statement 'With more and more people owning cars, the average number of passengers in a car on the road has dropped dramatically' most helps to explain why deaths and injuries resulting from automobile accidents have not increased significantly.