| Year | Value (SE) |
|---|---|
| 2009 | 0.3760 (0.0666) |
| 2010 | 0.6260 (0.1172) |
| 2011 | 0.6560 (0.1457) |
| 2012 | 0.3580 (0.0462) |
| 2013 | 0.5090 (0.0739) |
| 2014 | 0.4150 (0.0667) |
| 2016 | 0.5010 (0.0659) |
| 2017 | 0.3520 (0.0404) |
| 2018 | 0.6000 (0.1265) |
| 2019 | 0.3150 (0.0469) |
| 2020 | 0.4790 (0.0802) |
| 2021 | 0.3340 (0.1159) |
| 2022 | 0.5330 (0.3551) |
