Across US regions which amazon availability zones have historically been the most stable for EC2?
Amazon has [three regions available](http://aws.amazon.com/about-aws/globalinfrastructure/) for EC2 instances: US East (Northern Virginia), US West (Oregon), US West (Northern California). (We're not counting GovCloud (US) Region here.)

We know that availability zones within these regions have problems every now and then. Amazon provides [status on service availability](http://status.aws.amazon.com/) and thats helpful.

But I'm wondering if someone has studied the outages and come up with some reliability index for these various zones?
Across US regions which amazon availability zones have historically been the most stable for EC2?
===

Amazon has [three regions available](http://aws.amazon.com/about-aws/globalinfrastructure/) for EC2 instances: US East (Northern Virginia), US West (Oregon), US West (Northern California). (We're not counting GovCloud (US) Region here.)

We know that availability zones within these regions have problems every now and then. Amazon provides [status on service availability](http://status.aws.amazon.com/) and thats helpful.

But I'm wondering if someone has studied the outages and come up with some reliability index for these various zones?