| Year | Value (SE) |
|---|---|
| 2009 | 1.0200 (0.0307) |
| 2010 | 0.9340 (0.0721) |
| 2011 | 0.9610 (0.0146) |
| 2012 | 1.0190 (0.0240) |
| 2013 | 0.9460 (0.0537) |
| 2014 | 1.0930 (0.0410) |
| 2015 | 1.0690 (0.1494) |
| 2016 | 1.0240 (0.0362) |
| 2018 | 1.0400 (0.0310) |
| 2019 | 0.9790 (0.0165) |
| 2022 | 0.8230 (0.1351) |
| 2023 | 0.9010 (0.0584) |
| 2024 | 0.9300 (0.1654) |
