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. 2020 May 12;17(10):3360. doi: 10.3390/ijerph17103360

Table 1.

Quota used to select the study population.

US Sex and Age Breakdown Males Females
18–24 7% 7%
25–34 10% 10%
35–44 9% 9%
45–54 10% 10%
55–64 8% 9%
65–74 5% 6%
USA Regions
West 23%
Midwest 23%
South 36%
Northwest/Northeast 18%
USA Annual Income in US$
Less than 40,000 40%
More than 40,000 60%