| Year | Value (SE) |
|---|---|
| 2009 | 0.7354 (0.0611) |
| 2010 | 0.8042 (0.1049) |
| 2011 | 0.5489 (0.0340) |
| 2012 | 0.5797 (0.0561) |
| 2013 | 0.5457 (0.0826) |
| 2014 | 0.6144 (0.0682) |
| 2015 | 0.7084 (0.1983) |
| 2016 | 0.7221 (0.0656) |
| 2017 | 0.6416 (0.0930) |
| 2018 | 0.7050 (0.0908) |
| 2019 | 0.8233 (0.0650) |
| 2020 | 0.9235 (0.3170) |
| 2021 | 0.8032 (0.3527) |
| 2022 | 0.6043 (0.1894) |
