| Year | Value (SE) |
|---|---|
| 2009 | 0.4560 (0.0414) |
| 2010 | 0.3840 (0.0506) |
| 2011 | 0.4140 (0.0330) |
| 2012 | 0.4800 (0.0464) |
| 2013 | 0.5850 (0.0988) |
| 2014 | 0.7400 (0.0970) |
| 2015 | 0.4310 (0.0842) |
| 2016 | 0.4440 (0.0313) |
| 2018 | 0.4800 (0.0466) |
| 2019 | 0.4880 (0.0376) |
| 2022 | 0.4570 (0.1597) |
| 2023 | 0.5110 (0.0594) |
| 2024 | 0.3710 (0.1071) |
