If I were to make a guess, I would say the average mask wearing in Idaho is 5%. Medical facilities are the only places I know of that still insist on and enforce masks. Pretty much no one else even has signs out.
In areas like where I live, it seems to be closer to 1%, and mostly elderly, which is totally understandable and hey, it might protect them during cold and flu season. As I go in to cities in the Treasure Valley, I would say it goes up to 5% with more of an age mix. I don't frequent a lot of businesses over the border in Boise, but it seems closer to 10-15% of people there wear masks, again across age groups. There might still be private businesses there, like restaurants, that enforce masks, but I wouldn't know.
When I go into Ontario, in Oregon, I would also call it around 5-10%, again across age groups. There are still a lot of signs there, but no enforcement.