Geography of included studies
| Country | No. of studies | Percentage of studies |
|---|---|---|
| USA | 162 | 53.8 |
| UK | 38 | 12.6 |
| Australia | 27 | 9.0 |
| Japan | 12 | 4.0 |
| Canada | 10 | 3.3 |
| South Korea | 10 | 3.3 |
| Germany | 8 | 2.7 |
| China | 4 | 1.3 |
| Sweden, Norway, New Zealand, Switzerland, Spain, France | 3 each | 1.0 each |
| Finland, Austria, Thailand | 2 each | 0.7 each |
| India, Singapore, the Netherlands, South Africa, Italy | 1 each | 0.3 each |
| All | 301 | 99.9 |