That sounds low... Really low. E.g. NYC has ~350k employees and I know they got hit hard. Not all of them have windows machines, but let's say 100k do. I know they basically all have falcon installed. That's 100k in just one org, not even counting their windows servers. How many Fortune 500s are mainly Windows?
Edit: I did some back of napkin math. ~30 million work for a fortune 500. Let's say 2/3rds of those have a Windows desktop provided by employer, so ~20M. I think I read crowdstrike has about ~25% market share, so that's 5 mil just in fortune 500. No way it's just 8.5M