I was wondering the same thing. I got my license in 1983 and gas was less than CDN$.50/liter at that time, and the Cdn dollar was worth about USD$.85, IIRC. By my calculation that would have made gas about USD$1.60/US gallon, at the worst.
There are 3.785 L in a US gallon. Even today regular at $.80/L that's about $2.50us a us gallon . And I bought gas Friday for .729/L.