| Year | Value (SE) |
|---|---|
| 2011 | 0.9555 (0.2350) |
| 2012 | 0.6644 (0.1535) |
| 2013 | 0.8758 (0.2177) |
| 2014 | 0.4992 (0.1410) |
| 2015 | 0.5800 (0.1503) |
| 2016 | 0.4002 (0.0935) |
| 2017 | 0.5170 (0.1239) |
| 2018 | 0.5425 (0.1706) |
| 2019 | 0.4982 (0.1761) |
| 2020 | 0.5234 (0.2098) |
| 2021 | 0.7037 (0.5776) |
| 2022 | 1.3501 (0.7293) |
| 2023 | 0.6384 (0.2911) |
