It used to be decennial, but I forget when they changed it over.

Talk about naive youth(ish). I lived in an apartment during the 1991 census. I received a short form but my neighbour two doors down had moved out and he had a "long" one (the census was "hung" on the door "knobs" of each unit).

I wanted to fill out the long one so I called Stats Can's toll-free info line and asked if were permitted. I was told I could, so I did. Weeks(?) later I get a call from some woman badgering me for not filling out the form. I kept explaining to her what had transpired and even provided the individual number of the actual census I had filled out. She kept on and on and on at me. I didn't have the sense to hang up or get her name and phone in a complaint. I finally broke down and answered the questions for the short one, which means I was counted twice in that census. She obviously got paid by the census and didn't give a shit if I had already been included (and presumably my former neighbour, wherever he was, was included also).

This is one of those stupid things that grates on me for not standing up for myself.