| Year | Value (SE) |
|---|---|
| 2011 | 1.0420 (0.2504) |
| 2012 | 0.8034 (0.1832) |
| 2013 | 0.9863 (0.2413) |
| 2014 | 0.4623 (0.1294) |
| 2015 | 0.6856 (0.1675) |
| 2016 | 0.3758 (0.0859) |
| 2017 | 0.5869 (0.1200) |
| 2018 | 0.7009 (0.2183) |
| 2019 | 0.5457 (0.1869) |
| 2020 | 0.8524 (0.2968) |
| 2021 | 1.8865 (1.1794) |
| 2022 | 1.9739 (1.0142) |
| 2023 | 0.6763 (0.3033) |
