| Year | Value (SE) |
|---|---|
| 2005 | 0.6902 (0.0189) |
| 2006 | 0.7291 (0.0185) |
| 2007 | 0.9837 (0.2689) |
| 2008 | 0.7289 (0.0718) |
| 2009 | 0.8319 (0.0215) |
| 2010 | 0.7004 (0.0437) |
| 2011 | 0.7618 (0.0165) |
| 2012 | 0.8086 (0.0163) |
| 2013 | 0.7428 (0.0331) |
| 2014 | 0.7724 (0.0331) |
| 2016 | 0.8050 (0.0192) |
| 2017 | 0.7737 (0.0179) |
| 2018 | 0.7959 (0.0192) |
| 2019 | 0.7872 (0.0225) |
| 2020 | 1.0747 (0.1539) |
| 2021 | 0.7459 (0.1011) |
| 2022 | 0.5563 (0.0703) |
| 2023 | 0.8452 (0.0681) |
| 2024 | 0.6994 (0.1156) |
