| Year | Value (SE) |
|---|---|
| 2004 | 1.0880 (0.0373) |
| 2010 | 1.1990 (0.1267) |
| 2011 | 1.0330 (0.0480) |
| 2012 | 0.9290 (0.0395) |
| 2013 | 1.0620 (0.0867) |
| 2014 | 1.0150 (0.0514) |
| 2015 | 1.1530 (0.2180) |
| 2016 | 0.9930 (0.0267) |
| 2019 | 0.8440 (0.0631) |
| 2020 | 0.8410 (0.1009) |
| 2022 | 0.7870 (0.1211) |
| 2023 | 0.9890 (0.0932) |
