Table 2

Study characteristics

Study characteristics (n=12)Count (%)
Year of publication
 2002–20055 (41.7%)
 2006–20102 (16.7%)
 2010–20155 (41.7%)
Location
 USA6 (50%)
 Canada2 (16.7%)
 Australia2 (16.7%)
 The Netherlands2 (16.7%)