I hadn't spotted the Geekzone Dashboard before now (in the Site Features area at the bottom of the page), and had a quick poke around.  That PowerBI is pretty impressive.

I was interested to see that traffic from the USA was quite high, but trying different filters by year, I see the US traffic really drops off around 2011.  I had wondered whether the NZ traffic increased significantly to drown the US traffic, but it looks to me (with an in-depth analysis involving a 60 second fiddle with the filters) more like the US traffic slowed down.