| Year | Value (SE) |
|---|---|
| 2012 | 0.9900 (0.0399) |
| 2013 | 1.1030 (0.0940) |
| 2014 | 0.9910 (0.0606) |
| 2015 | 1.2830 (0.2506) |
| 2016 | 0.9050 (0.0461) |
| 2017 | 0.9080 (0.0333) |
| 2018 | 0.9770 (0.0522) |
| 2019 | 1.0380 (0.0447) |
| 2020 | 0.9760 (0.2003) |
| 2021 | 1.5760 (0.6371) |
| 2022 | 0.8300 (0.1983) |
| 2023 | 1.0220 (0.1221) |
| 2024 | 1.4250 (0.5725) |
