Not once a year, but here in new zealand for most people the email address is provided by the ISP.
When they change their ISP, they typically get a new email address.
Most people I know have changed their ISP a couple of times.
Also, to the extent to which this becomes important, it only becomes important too late, as in after you've already used an address or two. I have had the same address now since 1997 when I registered saurik.com, but I did that because I had in the two years prior "learned the hard lesson" that my ISP-provided e-mail address was doomed to be something I'd end up having to move off of, potentially fairly often.