| Year | Value (SE) |
|---|---|
| 2009 | 0.8635 (0.0548) |
| 2010 | 1.3144 (0.3378) |
| 2011 | 0.7052 (0.0162) |
| 2012 | 0.6169 (0.0190) |
| 2013 | 0.7464 (0.0565) |
| 2014 | 0.6393 (0.0610) |
| 2015 | 0.6136 (0.1075) |
| 2016 | 0.8241 (0.0338) |
| 2017 | 0.6730 (0.0393) |
| 2018 | 0.7059 (0.0824) |
| 2019 | 0.6655 (0.0626) |
| 2020 | 1.0907 (0.5299) |
| 2022 | 0.8569 (0.2267) |
| 2023 | 0.8299 (0.0864) |
