[By 1979 half of the gasoline in the US was unleaded](http://66.147.244.135/~enviror4/about/ethyl-leaded-gasoline/lead-history-timeline/ http://66.147.244.135/~

[By 1979 half of the gasoline in the US was unleaded](http://66.147.244.135/~enviror4/about/ethyl-leaded-gasoline/lead-history-timeline/ http://66.147.244.135/~enviror4/about/ethyl-leaded-gasoline/...). So by the early eighties it was mostly gone. So yeah, I slightly misspoke saying it was mostly gone in the 70s, but it was halfway gone by then.