I don't believe it is a small number. There's about 200 nations in the world and I suspect that the number that still have Morse code testing is more than those that do not. A few that some to mind with Morse code testing yet is Brazil, Japan, and India. I suspect most nations in Africa and Asia still require such testing. I suspect most nations in South America require Morse code testing but there is an option of an IARP to operate there which doesn't require Morse code proficiency shown on a government issued license. To answer your question directly, I don't know. Whenever it comes to mind I'll search the web for a definitive list but keep coming up empty. I do recall that this problem has come to my attention since the FCC started paring back the Morse code proficiency testing so many years ago. I can vaguely (and perhaps incorrectly) recall people looking for ways to prove 10 WPM Morse code proficiency when the FCC only required showing 5 WPM. Around that time many nations were following the lead of the USA and FCC by dropping their requirements to 5 WPM too. The elimination of Morse code testing completely didn't happen nearly as quickly though.