| Year | Value (SE) |
|---|---|
| 2000 | 0.7465 (0.0808) |
| 2002 | 0.7352 (0.0261) |
| 2003 | 0.7663 (0.0331) |
| 2004 | 0.5880 (0.0452) |
| 2005 | 0.7306 (0.0551) |
| 2006 | 0.7351 (0.0248) |
| 2007 | 0.8065 (0.0169) |
| 2008 | 0.7264 (0.0540) |
| 2009 | 0.6194 (0.0427) |
| 2010 | 0.9225 (0.0699) |
| 2011 | 0.6609 (0.0369) |
| 2012 | 0.7823 (0.0329) |
| 2013 | 0.7620 (0.0542) |
| 2014 | 0.8847 (0.0586) |
| 2015 | 0.5278 (0.0754) |
| 2016 | 0.6571 (0.0382) |
| 2017 | 0.4230 (0.0351) |
| 2020 | 0.6919 (0.1694) |
| 2021 | 0.8352 (0.3888) |
| 2022 | 0.8165 (0.3359) |
| 2023 | 0.5735 (0.0731) |
