Systematically Delete Rows

Hey Folks,

I got a really huge time series data set that I would like to reduce by 80%.

The dates are in column A and the values are in column C.

I'd like to keep rows 1, 6, 11,16, ... And delete Rows 2, 3, 4, 5, 7, 8, 9, 10, ...

I'm guessing there's some really simple way to do this that I just don't know about.