Schtick, I'm just guessing on this. If Apple has a record of the name of each Apple/Mac computer purchaser through the registration process over these many years, then all they would have to do is compare new to old names. Presumably the percentage of new names in a given time period would represent the switchers.
I think a lot of people say "oh, I used to use an Apple Computer." I actually hear it quite a bit. It's almost like oh yeah, don't criticize me for using/owning a PC, I actually learned on an Apple computer. Most sound proud of that legacy so if they fill out a form, do they say they are a previous Apple or Mac user?
News 
Market Data 
Discover 
AI
