GMail conveniently discards spam older than 30 days. This means that the number of messages in the spam folder at any given time represents an estimate of monthly spam volume. I've been watching that folder swell lately to over 5500 spam messages over the past month. It made me wonder, "How many real emails do I get in that time?"
Well it turns out that in November I received 246 real mails to my gmail address (which includes forwards from my alum.mit.edu address) and 5514 spams. That means that email going to that address is a shocking 96% spam! Nearly all of it is automatically filtered, of course; otherwise the address would be unusable.