| Year | Value (SE) |
|---|---|
| 2009 | 0.8160 (0.0677) |
| 2010 | 0.9214 (0.1145) |
| 2011 | 0.8022 (0.0488) |
| 2012 | 0.9360 (0.0897) |
| 2013 | 0.8213 (0.1219) |
| 2014 | 0.7856 (0.0865) |
| 2015 | 0.7570 (0.2092) |
| 2016 | 0.8846 (0.0799) |
| 2017 | 0.6434 (0.0925) |
| 2018 | 0.8750 (0.1112) |
| 2019 | 1.0404 (0.0816) |
| 2020 | 1.1034 (0.3788) |
| 2021 | 0.5405 (0.2375) |
| 2022 | 0.9085 (0.2853) |
