| Year | Value (SE) |
|---|---|
| 2003 | 0.5050 (0.0132) |
| 2010 | 0.6069 (0.0518) |
| 2011 | 0.4779 (0.0426) |
| 2012 | 0.6677 (0.0740) |
| 2013 | 0.5253 (0.0703) |
| 2014 | 0.3893 (0.0562) |
| 2015 | 0.5003 (0.0968) |
| 2017 | 0.4208 (0.0508) |
| 2018 | 0.3699 (0.0631) |
| 2019 | 0.3444 (0.0685) |
| 2020 | 0.5720 (0.1535) |
| 2021 | 0.5746 (0.2202) |
| 2022 | 0.2396 (0.0955) |
| 2023 | 0.6483 (0.2725) |
