| Year | Value (SE) |
|---|---|
| 2012 | 0.9623 (0.0413) |
| 2013 | 0.9177 (0.0831) |
| 2014 | 0.9494 (0.0603) |
| 2015 | 1.3279 (0.2650) |
| 2016 | 0.8923 (0.0459) |
| 2017 | 0.8680 (0.0338) |
| 2018 | 0.9780 (0.0538) |
| 2019 | 1.0069 (0.0443) |
| 2020 | 0.8560 (0.1755) |
| 2021 | 1.5492 (0.6259) |
| 2022 | 0.7561 (0.1797) |
| 2023 | 1.0261 (0.1225) |
| 2024 | 1.4906 (0.5989) |
