You forgot to SAY that Nigeria leads because a quarter of its Population are involved in 419 Scams conning everyone on the internet…hence much Western Union inflows.
It would be excellent if the funds sent across were to be used for investment purposes rather than paying off hospital bills and buying (foreign) shoes and clothes. The application of the money to build Africa’s capacity is more important than its source. In fact, we could do with a law requiring money obtained through illegitimate means to be invested in capital goods in the country where it was obtained-there are indirect benefits compared to when it is pulled out of the economy and sent elsewhere. Africa would be a major beneficiary in such circumstances.