I don't know the exact stats, but very few have been deleted from
supercharge.info. We maintain a spreadsheet for our
Superchargers Visited game, and do very few deletes.
Here are some numbers that may help:
Number of superchargers currently in
supercharge.info is 2348
Highest supercharger id (assigned sequentially) with the first one being 100 is 2652
We have 15 in our spreadsheet that were opened than closed, and were deleted from
supercharge.info
(our spreadsheet only has US, Canada)
Superchargers that were opened then closed are now kept in supercharge.info and marked as closed. I've never personally deleted a supercharger from
supercharge.info, but I know it happens.
"Coming Soon" superchargers on the Tesla "find us" page are not put in
supercharge.info until there is a permit of other evidence that it is real, so it is not a source for determining locations dropped from the "find us" page.