Side air bags have increased in popularity in the last 25 years. Although it looks like they reached 100% in 2012, so presence of side air bags doesn't explain

Side air bags have increased in popularity in the last 25 years. Although it looks like they reached 100% in 2012, so presence of side air bags doesn't explain changes in the last 10 years. https://www.statista.com/statistics/688636/penetration-rate-of-side-airbags-in-us-cars/ https://www.statista.com/statistics/688636/penetration-rate-...