| Year | Value (SE) |
|---|---|
| 2004 | 0.7120 (0.2264) |
| 2010 | 0.8553 (0.2345) |
| 2011 | 0.6829 (0.2621) |
| 2012 | 0.6873 (0.1158) |
| 2013 | 0.5749 (0.1470) |
| 2014 | 0.5662 (0.1247) |
| 2015 | 0.9499 (0.6301) |
| 2016 | 0.5205 (0.0677) |
| 2019 | 0.5932 (0.1491) |
| 2020 | 0.7036 (0.2504) |
| 2022 | 0.5649 (0.4653) |
| 2023 | 1.0082 (0.5736) |
