| Year | Value (SE) |
|---|---|
| 2012 | 0.7727 (0.0333) |
| 2013 | 0.5965 (0.0540) |
| 2014 | 0.8174 (0.0519) |
| 2015 | 1.0092 (0.2013) |
| 2016 | 0.7558 (0.0390) |
| 2017 | 0.7760 (0.0303) |
| 2018 | 0.8186 (0.0450) |
| 2019 | 0.7793 (0.0344) |
| 2020 | 0.6976 (0.1431) |
| 2021 | 1.2363 (0.4995) |
| 2022 | 0.5542 (0.1317) |
| 2023 | 0.8260 (0.0987) |
| 2024 | 1.2387 (0.4977) |
