| Year | Value (SE) |
|---|---|
| 2000 | 0.5190 (0.0946) |
| 2001 | 0.7990 (0.0445) |
| 2002 | 0.9820 (0.0915) |
| 2003 | 0.8450 (0.0369) |
| 2004 | 0.7140 (0.0945) |
| 2007 | 0.8580 (0.0448) |
| 2010 | 0.8910 (0.1028) |
| 2011 | 0.9530 (0.1249) |
| 2012 | 0.7260 (0.0661) |
| 2013 | 0.7970 (0.1067) |
| 2014 | 1.0380 (0.1379) |
| 2015 | 0.9640 (0.1933) |
| 2016 | 0.8850 (0.0812) |
| 2017 | 0.8540 (0.0925) |
| 2018 | 0.8880 (0.0651) |
| 2022 | 0.2740 (0.1618) |
| 2023 | 0.8340 (0.2690) |
