| Year | Value (SE) |
|---|---|
| 2009 | 0.5691 (0.0717) |
| 2010 | 0.5728 (0.1335) |
| 2011 | 0.5988 (0.0560) |
| 2012 | 0.7295 (0.0936) |
| 2013 | 0.9437 (0.2094) |
| 2014 | 0.8373 (0.1440) |
| 2015 | 0.5344 (0.1759) |
| 2016 | 0.5683 (0.0616) |
| 2018 | 0.5971 (0.1053) |
| 2019 | 0.7099 (0.0789) |
| 2022 | 0.8021 (0.4909) |
| 2023 | 0.7332 (0.1872) |
| 2024 | 0.5213 (0.2553) |
