Personally, I'm thinking that the most accurate stats tracker for Mastodon is the-federation.info.
But even that has issues that are perplexing.
For example, the-federation.info lists mastodon.social as having 993,783 accounts -- all of which are apparently active during the past 6 months. Yeah, I don't buy that.
@atomicpoet Ah, but I didn't entirely catch that you were questioning the accuracy of these stats. They also could be wrong. But to give you an good opinion about that I would have to look into the stats and I don't have time for that :(