| Year | Value (SE) |
|---|---|
| 2009 | 1.0230 (0.0255) |
| 2010 | 0.9560 (0.0591) |
| 2011 | 0.9720 (0.0174) |
| 2012 | 0.9830 (0.0188) |
| 2013 | 1.1260 (0.0706) |
| 2014 | 1.0540 (0.0341) |
| 2015 | 1.3370 (0.1236) |
| 2016 | 1.0840 (0.0431) |
| 2017 | 1.0970 (0.0574) |
| 2018 | 0.9850 (0.0369) |
| 2019 | 0.9410 (0.0166) |
| 2020 | 1.0120 (0.1099) |
| 2021 | 1.9150 (0.4858) |
| 2022 | 0.8430 (0.1093) |
