| Year | Value (SE) |
|---|---|
| 2012 | 0.8540 (0.0373) |
| 2013 | 0.8219 (0.0768) |
| 2014 | 1.0164 (0.1309) |
| 2015 | 0.9408 (0.2152) |
| 2016 | 0.8674 (0.0576) |
| 2017 | 0.8092 (0.0338) |
| 2018 | 0.8389 (0.0677) |
| 2020 | 0.5480 (0.1977) |
| 2021 | 2.7963 (2.8185) |
| 2022 | 0.6380 (0.1978) |
| 2023 | 0.7034 (0.0669) |
| 2025 | 0.9876 (0.5887) |
