| Year | Value (SE) |
|---|---|
| 2012 | 0.6684 (0.0584) |
| 2013 | 0.4736 (0.0530) |
| 2014 | 0.6433 (0.0514) |
| 2015 | 0.6186 (0.1314) |
| 2016 | 0.6507 (0.0488) |
| 2017 | 0.7202 (0.0570) |
| 2018 | 0.6999 (0.0839) |
| 2019 | 0.5821 (0.0472) |
| 2020 | 0.8525 (0.2188) |
| 2021 | 0.7875 (0.3382) |
| 2022 | 0.4983 (0.1504) |
| 2023 | 0.4427 (0.0869) |
| 2024 | 0.6292 (0.2844) |
