| Year | Value (SE) |
|---|---|
| 2009 | 0.9054 (0.0436) |
| 2010 | 1.1396 (0.1290) |
| 2011 | 0.9283 (0.0276) |
| 2012 | 0.9476 (0.0333) |
| 2013 | 1.2600 (0.1575) |
| 2014 | 1.0740 (0.0805) |
| 2015 | 1.6646 (0.4471) |
| 2016 | 0.9886 (0.0683) |
| 2017 | 0.9500 (0.0742) |
| 2018 | 0.9357 (0.0610) |
| 2019 | 0.9561 (0.0286) |
| 2020 | 1.2164 (0.3383) |
| 2021 | 0.7143 (0.2888) |
| 2022 | 0.5960 (0.1195) |
