| Year | Value (SE) |
|---|---|
| 2000 | 0.6338 (0.1151) |
| 2001 | 0.1890 (0.0143) |
| 2008 | 0.7829 (0.0385) |
| 2009 | 0.7475 (0.0260) |
| 2010 | 0.7801 (0.0366) |
| 2011 | 0.6572 (0.0185) |
| 2012 | 0.7907 (0.0315) |
| 2013 | 0.7738 (0.0647) |
| 2014 | 0.7713 (0.0588) |
| 2015 | 0.9970 (0.1865) |
| 2016 | 0.9110 (0.0443) |
| 2017 | 0.7962 (0.0369) |
| 2018 | 0.6784 (0.0532) |
| 2019 | 0.6389 (0.0353) |
| 2020 | 0.7398 (0.1536) |
| 2021 | 0.6561 (0.2793) |
| 2022 | 0.9550 (0.3224) |
| 2023 | 0.9797 (0.1552) |
