Table S3.

Location (country) where the N=54 studies published from 1997 to August 2013 were conducted

Rank	Country	Number of studies
1	USA	16
2	Australia	7
3	Spain	6
4	Germany	4
5	People’s Republic of China, France, Italy	3 each
6	Austria, Canada, Denmark, UK	2 each
7	Brazil, India, the Netherlands, Switzerland, Taiwan, Turkey	1 each

Note: N does not add up to 54 because some studies were conducted in more than one country.