Most? A very large chunk use spaces or thin-spaces as thousand separators. By GDP, at least, periods are probably in the minority.

Germany, Italy, Spain, Netherlands, Belgium at least appear to use a period as the thousands separator. Quite of lot of population and GDP there already.

At least Belgium officially uses spaces as thousands seperator [0]

[0] http://ond.vvkso-ict.com/vvksomainnieuw/brochure/Vouwblad%20...

The spaces is an iso standard.

Most Europeans I’ve talked to use “,” for the radix and “.” For the separator.

Personally I really like spaces since they’re unambiguous.

European here, in my corner we use spaces for thousands separator and commas for the radix.

But hey, we have several different standards for power plugs and outlets, so no surprise that other stuff is different too.

> Personally I really like spaces since they’re unambiguous.

But not if you are writing with a pen or pencil, a visible token makes way more sense.

I've seen '⎵' commonly used as an unambiguous space. Maybe that could work?