Best time to buy RS3 GP?

Just wanted to see when is generally the best time of year to purchase RS3 GP. I know last year, especially throughout summer to early winter, GP was going for prices as low at $0.07/m, with a few exceptions dropping even lower. Right now, I see the average is about $0.09/m.

Also, is there perhaps a graph anywhere that someone made that has been taking averages, watching the RWTing GP sales for the past few years? Want to get the most for my dollar, so just planning timing.

 

The cheapest gold is always when there's some kind of exploit that gives opportunity for GP dupe. It happens atleast like once per year.