| Year | Value (SE) |
|---|---|
| 2001 | 0.3036 (0.0163) |
| 2006 | 0.7869 (0.0134) |
| 2007 | 0.6253 (0.0305) |
| 2008 | 0.6782 (0.0212) |
| 2009 | 0.8622 (0.0285) |
| 2010 | 0.7448 (0.0149) |
| 2011 | 0.7828 (0.0185) |
| 2012 | 0.8094 (0.0148) |
| 2013 | 0.7547 (0.0554) |
| 2014 | 0.8137 (0.0512) |
| 2015 | 0.5268 (0.0790) |
| 2016 | 0.6005 (0.0408) |
| 2018 | 0.5324 (0.0372) |
| 2020 | 0.6740 (0.0803) |
| 2021 | 0.5895 (0.1130) |
| 2022 | 0.4586 (0.0475) |
| 2023 | 0.6198 (0.0590) |
| 2024 | 0.7768 (0.1781) |
