The Scandinavian countries have probably the lowest levels of mask wearing in the developed world. Doesn’t seem to have affected their case levels when compared to the rest of Europe, as this chart, courtesy of Twitter, demonstrates. No masks, no problem, apparently. Little hard to read the inset cart but the reddish area is the percent of people who say they always wear a mask in these countries and the darker gray area is the percent who say they never do. I really want a mask nut to explain this.
The Healthy Skeptic is a website about the health care system, and is written by Kevin Roche, who has many years of experience working in the health industry. Mr. Roche is available to assist health care companies through consulting arrangements through Roche Consulting, LLC and may be reached at 
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What was the actual question that was asked and how many people were asked the question? Were the respondents from different households? I like the results but there is information missing.
This is the large survey I reported on originally a few weeks ago, I believe the NYTimes or some news organization was one of the original sponsoring groups. As I recall it was pretty large and randomized, but all phone surveys have potential bias issues. This was fairly credible work and has been used in other research. If you look at pictures from the Scandinavian countries, no one is wearing a mask.