[DoodleBob]

Here is the longer-term trend. We could argue that the aging of the planet is begetting lower fatalities from this chart.

But a visual correlation doesn't prove causality. Perhaps your chart is, like this one, is measuring the aggregate and continuous enhancement in product safety, driver learning, better road markers, and other things like air bags as well as seat belts.

[ProtectOurFreedom]

No doubt all those things cumulatiively contributed to reduced fatality rates. A 24:1 reduction in 90 years is really astonishing.

There were many product safety improvements that contributed. Many (most?) were mandated by government, too. Sometimes (rarely) the government does a good job.