Year Before Last
Remember how 一昨日 means "day before last"? Similarly, one year previous to that year is the year before last.
The last time you tossed something into a trash can was the year before last. Why? Because you got a trash can with an auto tossing (おととし) feature. What amazing technology!
He was born in January two years ago.
Who was the mayor two years ago again?
I have been jogging every day since two years ago.