| Year | Value (SE) |
|---|---|
| 2012 | 1.2100 (0.1401) |
| 2013 | 0.9430 (0.1608) |
| 2014 | 1.1570 (0.2118) |
| 2015 | 1.0490 (0.2556) |
| 2016 | 0.8390 (0.0986) |
| 2017 | 0.9980 (0.1028) |
| 2018 | 1.2560 (0.2559) |
| 2020 | 0.6860 (0.2531) |
| 2021 | 1.9060 (0.8103) |
| 2022 | 1.1990 (0.6235) |
| 2023 | 1.2890 (0.4477) |
| 2025 | 1.3510 (0.7081) |
