| Year | Value (SE) |
|---|---|
| 2011 | 0.9320 (0.2199) |
| 2012 | 1.0300 (0.2160) |
| 2013 | 1.3950 (0.3162) |
| 2014 | 0.7970 (0.2009) |
| 2015 | 0.7240 (0.1246) |
| 2016 | 0.6100 (0.1166) |
| 2017 | 0.9360 (0.1655) |
| 2018 | 0.7370 (0.2213) |
| 2019 | 0.9850 (0.3126) |
| 2020 | 1.0790 (0.2467) |
| 2021 | 1.3720 (0.5878) |
| 2022 | 3.0650 (1.4824) |
| 2023 | 1.0820 (0.4571) |
