I’m not a physicist, but even if Astatine is being produced in minute quantities by decay, a half life of 8hrs should probably put it lower on the numbers than Americium.

Americium is produced anywhere you have lots of free neutrons. This may be rare on earth outside of nuclear power plants and bomb test sites, but not necessarily rare in the universe. Especially since it has a half life of 432years, so unlike astatine it can actually accumulate a bit and not just decay immediately.

Astatine basically doesn’t exist. The total amount in the entirety of earth’s crust at any given time is estimated to be less than a gram.

So I feel like the amounts should be flipped or at the very least closer in orders of magnitude.