I'm gonna throw in an observation here.
We've been looking at these numbers for 2 months now, with the number of responses slowly rising.
But the displayed number of FOID cards that we are comparing against is not changing.
So that number 2,415,481 is dated, but how old is it?
archive.org shows a June version with the same FOID card count, but it's always possible that it's a dynamic lookup.
https://web.archive.org/web/20230601175455/https://isp.illinois.gov/Foid/Statistics
The 0.2% response number could be somewhat lower.