Yes it happens every year in Canada on the 1st of July.
It is a triennial event. A triennial event happens three times a year.
A triennial event happens every three years.
yes i'm positive it happens every year
Something that happens every six years is sexennial.
nothing
bidecadal
Semicentennial
I think you are asking about a census.
An event occurring every two years is referred to as a biennial event. This pattern indicates that the event happens once every two years.
The cast of It Happens Every Day - 1919 includes: Adolf Philipp
twice-a-day or it can be called semi-diurnal which relates to such occurrences as tides.