Verify relation statistical sectors - munipalities in post-2019 data

[mhermans]

From https://statbel.fgov.be/nl/open-data/statistische-sectoren-2020 :

"Vanaf de toestand 01012019 kan de gemeente code niet meer uit de statistische sectorcode afgeleid worden"

It is unclear to me if this is a mismatch at the level of the identifier (no longer a clean link with the first x digits of the sector-identifier), or a spatial mismatch (no longer perfectly nested).

I'm currently guessing the first, which does not really pose a problem for aggregating sectors to municipalities and higher levels. Aggergating sectors on municipal identifier cnis5_2020 seems to at least give the proper number of municipalities.

TODO: verify what this change means, and if a workaround / different hierachy-file is needed.

[jwijffels]

My guess is also the first, in which case indeed there is no issue.