| Year | Value (SE) |
|---|---|
| 2000 | 1.2436 (0.8817) |
| 2001 | 0.0705 (0.0183) |
| 2008 | 0.6531 (0.0409) |
| 2009 | 0.6814 (0.0391) |
| 2010 | 0.6242 (0.0363) |
| 2011 | 0.5601 (0.0304) |
| 2012 | 0.7432 (0.0506) |
| 2013 | 0.6568 (0.0742) |
| 2014 | 0.8043 (0.0780) |
| 2015 | 0.6947 (0.1679) |
| 2016 | 0.8400 (0.0597) |
| 2017 | 0.6243 (0.0423) |
| 2018 | 0.6465 (0.0599) |
| 2019 | 0.6109 (0.0484) |
| 2020 | 0.8788 (0.1966) |
| 2021 | 0.6208 (0.2767) |
| 2022 | 0.7390 (0.2976) |
| 2023 | 0.6246 (0.1046) |
