I'll add a third to the motion. And I think we can add Canada to the USA in this regard - not sure about the absolute wording of the regs but "Declaring an Emergency" is the norm here. In over 40 years I never heard "Mayday" and only a very few "Pans" but plenty of "Declarings".
It has always amused me that the UK produces the most R/T Police (Nigel comes to mind) yet it has numerous weird deviations from normal R/T that the rest of the world is expected to follow - FL One Hundred comes to mind.