| Year | Value (SE) |
|---|---|
| 2012 | 0.8763 (0.1087) |
| 2013 | 0.8379 (0.1610) |
| 2014 | 0.9744 (0.2183) |
| 2015 | 0.7597 (0.2523) |
| 2016 | 0.6341 (0.0866) |
| 2017 | 0.8684 (0.0966) |
| 2018 | 0.8209 (0.1808) |
| 2020 | 0.7265 (0.3766) |
| 2021 | 1.2812 (1.4022) |
| 2022 | 0.8078 (0.4918) |
| 2023 | 0.8946 (0.3236) |
| 2025 | 0.4961 (0.3947) |
