TABLE 5.

List of studies by country of origin

Country	n	References
United Kingdom	26	14, 16, 17, 20, 21, 23, 24, 27, 28, 29–33, 36–39, 43–45, 49, 52–56
United States	6	15, 22, 25, 26, 34, 46
Canada	5	29, 40, 42, 50, 51
Sweden	2	47, 48
Switzerland	2	19, 35
Iran	1	41
South Korea	1	18