| Year | Value (SE) |
|---|---|
| 2000 | 1.0440 (0.1047) |
| 2006 | 1.0860 (0.0810) |
| 2008 | 0.8380 (0.0353) |
| 2009 | 0.8420 (0.0363) |
| 2010 | 0.8930 (0.0570) |
| 2011 | 0.9950 (0.0203) |
| 2012 | 0.4690 (0.1695) |
| 2013 | 0.9660 (0.0339) |
| 2014 | 0.9590 (0.0286) |
| 2016 | 0.8390 (0.0277) |
| 2017 | 0.8580 (0.0269) |
| 2018 | 0.8960 (0.0454) |
| 2019 | 0.8650 (0.0532) |
| 2020 | 0.6800 (0.0958) |
| 2021 | 2.8050 (1.0592) |
| 2022 | 0.9210 (0.3035) |
| 2023 | 0.5420 (0.1796) |
| 2024 | 0.8820 (0.1266) |
