Several official documents published by the World Bank's 'International Bank For Reconstruction and Development' (IBRD), such as https://pubdocs.worldbank.org/en/795101541106471736/IBRDCountryVotingTable.pdf
feature tables of all the subscriptions listed by country. Noticeably, the dollar amounts are measured in '1944 US dollars'.
Considering some of the listed countries didn't even exist in 1944, or had convertible currencies, it seems rather difficult to understand how this amount is calculated or why it's still being used.
I've not been able to find any literature online that would explain the rationale, so any insight anyone may have would be appreciated.