I doubt whether those US numbers are real, lot of custom rom development/user base has been asian & european market in last decade even though the numbers have been decreasing over the decade (I don't have proof)...

Using a custom ROM is not the same as using LineageOS in particular. Also, the numbers imply just 23% of LineageOS installs are in the US.

Partially agree, as LOS is no where used as OEM and people familar with custom rom eventually would have used LOS (not mendatory but the numbers would relate)