They were still being used in 1970. My first job after I was discharged from the army, was working for an Agri-supply company. My job was totaling tobacco tickets. I used the electric version. It was hard to learn how to use it and difficult to be accurate.
All these machines do is give out change. Need 47 cents then push 47 and out comes 1 quarter, 2 dimes and 2 pennies. Want 76 cents push 76 and you get 3 quarters and 1 penny. No adding on these machine and they are absolutely accurate.