geocoding - Average frequency of zip code change for a given address over the course of year

This is a difficult question to answer with a high degree of accuracy, but could someone estimate to within an order of magnitude for me the chances of a zip code for a given address changing over the course of a year?

For example, would you say the chances of this are:

a) ~10%

b) ~1%

c) ~.1%

d) ~.01%

Just trying to get a rough sense of the constancy of these things for some code I'm writing. If the answer were ~10% I would proceed very differently than if it were ~.01%.

Answer

I maintain the Zip Code feature class for the USPS. Of our 34,000~ Zip Codes, I alter the boundaries of maybe 5~ a month.

Some Zip Codes contain thousands of addresses, some contain less than one hundred.

Hard to estimate an average yearly change per address, I would say .01%