| Year | Value (SE) |
|---|---|
| 2009 | 0.8930 (0.0732) |
| 2010 | 0.9620 (0.1784) |
| 2011 | 0.7200 (0.0354) |
| 2012 | 0.7810 (0.0652) |
| 2013 | 0.8150 (0.1138) |
| 2014 | 1.0040 (0.1078) |
| 2015 | 0.7240 (0.1651) |
| 2016 | 0.8700 (0.0640) |
| 2018 | 0.7220 (0.1058) |
| 2019 | 0.7490 (0.0600) |
| 2022 | 0.5980 (0.2846) |
| 2023 | 0.5180 (0.1140) |
| 2024 | 0.9780 (0.3491) |
