Since Higgins house and servers were wiped out by Sandy, his very valuable website showing beta and gamma realtime charts is no longer available.
I wrote to him to ask for help on chart setup, it looks tricky, but he very likely has other priorites on his mind.
At this link is a scatter chart of recent readings,
Seattle spiking to 300 CPM last week!
Anything about 100 CPM is cause for concern. At 100 CPM you have a significant increase in cancer if you stay in the 100 CPM zone for 1 year.