>* - US (and maybe one or two English-speaking countries) are the only ones using 12h time, the rest of the world uses 24hrs, however 12h _sometimes_ is used conversationally;*

I think most countries use 12h time casually (conversationally and so on), but most understand 24h time - and it's used officially (e.g. in state communications) in many. It's in the US though that people often need it explained.