"Unknown mintage"

Hi guys,

Hope you are having a nice evening/day.

Have been wondering recently how a mintage number could be unknown (for modern coins). For example this coin (and many others): N#5364

This has been the official circulating legal tender in that country at some point. Surely, at least the central bank should've known how many were struck and circulating for obvious reasons.

Am I being crazy, or is it a valid point?

Thanks

The Central Bank does know but they're not telling.  Many Governments refuse to disclose how many coins and banknotes they make.