| Year | Value (SE) |
|---|---|
| 2012 | 0.7805 (0.0186) |
| 2013 | 0.5408 (0.0213) |
| 2014 | 0.8248 (0.0236) |
| 2015 | 0.7866 (0.0698) |
| 2016 | 0.8351 (0.0246) |
| 2017 | 0.8547 (0.0216) |
| 2018 | 0.8378 (0.0217) |
| 2019 | 0.7508 (0.0181) |
| 2020 | 0.7148 (0.0606) |
| 2021 | 0.7844 (0.1169) |
| 2022 | 0.6678 (0.1004) |
| 2023 | 0.8082 (0.0474) |
| 2024 | 0.8692 (0.1532) |
