I read a paper on this last week but I can't find it at the moment. However I recall them polling people on mask usage, and pre-SARS it was single digits percentage, post-SARS it was 85-90%.
Of course, it's much more common than Europe or the US, but it's still in the single digit percentages.
This was before the current pandemic of course. But eve today, in Singapore, I'd estimate 15% to 20%?