| Year | Value (SE) |
|---|---|
| 2009 | 0.9980 (0.1957) |
| 2010 | 0.9880 (0.2302) |
| 2011 | 1.5600 (0.3713) |
| 2012 | 0.9770 (0.1421) |
| 2013 | 0.8330 (0.1601) |
| 2014 | 0.8140 (0.1630) |
| 2016 | 1.1130 (0.1547) |
| 2017 | 0.8600 (0.1250) |
| 2018 | 1.1170 (0.2973) |
| 2019 | 0.9760 (0.2194) |
| 2020 | 1.2970 (0.3522) |
| 2021 | 0.9210 (0.3852) |
| 2022 | 2.3360 (1.7548) |
