Table 3.

Location of studies by country

Countries	Number of studies	Sources
USA	32	[48-52,54,57-59,66,67,69,71-75,77-88,95,96,98]
Australia	8	[53,60,61,64,65,76,93,94]
Canada	5	[56,63,70,89,97]
Netherlands	3	[90-92]
Canada and USA	1	[55]
Mexico and USA	1	[62]