| Year | Value (SE) |
|---|---|
| 2006 | 0.7097 (0.1170) |
| 2008 | 0.6096 (0.0939) |
| 2009 | 0.8161 (0.0805) |
| 2010 | 0.8231 (0.0678) |
| 2011 | 0.8930 (0.0798) |
| 2012 | 0.7596 (0.0865) |
| 2015 | 0.3481 (0.2269) |
| 2016 | 0.4459 (0.3013) |
| 2019 | 0.8375 (0.2861) |
| 2020 | 0.4742 (0.1890) |
| 2021 | 0.1442 (0.1043) |
| 2022 | 0.3674 (0.1009) |
| 2023 | 0.5446 (0.3958) |
