Oh, and remember that boats completing a circumnavigation during any year are thought to be less than 100 total of all nationalities.
From speaking to Americans I do get the idea they prefer countries where everyone speaks English. Canadians often have a bit of French and are not so worried about going to Europe, but there is definitely fewer (outright) Canadian flags than US.
There is always some Scandinavian boat, often small boats with young couples on board, or the Halberg Rassy brigade.
Aussies are everywhere because we are drunk and looking for cheap beer.
French only go to places that speak French, but that includes a lot of the Caribbean and the Pacific.
But by the time any boat has done 2 full oceans (No, "crossing the Atlantic" is NOT Florida to Nassau!!) it doesn't matter what nationality they have, they're all cruisers and are likely to be good company in any anchorage and helpful to any boat with the slightest problem.
Oh, and, ummmmm, yes, Americans still have the biggest flags. By far.