| Year | Value (SE) |
|---|---|
| 2003 | 1.0180 (0.0489) |
| 2010 | 1.0300 (0.1977) |
| 2011 | 1.0830 (0.2134) |
| 2012 | 0.6260 (0.0980) |
| 2013 | 0.9270 (0.2308) |
| 2014 | 1.0180 (0.2638) |
| 2015 | 0.5550 (0.1848) |
| 2017 | 1.1610 (0.2027) |
| 2018 | 1.3810 (0.4140) |
| 2019 | 1.4150 (0.4143) |
| 2020 | 0.9880 (0.3655) |
| 2021 | 1.7920 (1.8606) |
| 2022 | 3.0190 (2.0582) |
| 2023 | 0.4700 (0.2142) |
