From my new website (not yet released):That's a 1 month chart...

From my new website (not yet released):

That's a 1 month chart (ending June 1st) for both the global rank and local rank. For SWF, the local rank is of most importance (though I have less data for the local rank, just 15 days so far). If the local rank also had the full month of data, then the drop in the past few days would look less significant, because its scale would be larger.

It's similar to log scale, like going from rank 1000 to rank 100 might require something like 10x the traffic.