Table 2.
Years of publication of included studies.
| Year | Number of studies |
|---|---|
| 2002-2006 | 8 |
|
| |
| 2007-2011 | 10 |
|
| |
| 2012-2016 | 37 |
|
| |
| 2017-2018 (May) | 20 |
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