The cash cow that is the SA to Zim remittance corridor

Why don't SADC central banks like reporting which countries amount for the most in remittance out and inflows? I thought that it was a uniquely Zimbabwean issue but the South African Reserve Bank (SARB) seems to also be shy about publicising which countries receive the most from its bustling economy. I mean... SA is the largest remittance-sending nation in Africa and that kind of status should be an incentive to flex which SADC and other African regions depend on the stability of its economy.

That being said, it's not hard to find out which country sends out the most because diaspora population estimates make that bit of math easier. Zimbabwe has the most migrants, both informal and formal, who live in South Africa.

The exact number is a bit up in the air because there are a lot of undocumented people who crossed the border illegally to escape the hardships on the other side of the Limpopo River.

However, the figure that is commonly referenced is around a million, give or take a hundred thousand on either side. Additionally, many who quote any population figure tend to stress that it's an estimate because the true number is hard to get to...