I just received a small freebie (American) medical publication that, to my surprise, displayed some large numbers thus:
"...we do have a large amount of experience with more than 100 000 patients treated -- in some cases, more than 1 000 000 patients treated." This was part of a transcript of an interview, so it was obviously the publisher's choice about how to depict this. One advantage of spaces is that it eliminates the confusion with commas and periods used a sentence punctuation. (the poster formerly known as Greg)
