| Year | Value (SE) |
|---|---|
| 2000 | 0.9570 (0.0130) |
| 2001 | 0.7870 (0.0078) |
| 2002 | 0.8910 (0.0146) |
| 2003 | 0.9290 (0.0148) |
| 2004 | 0.9420 (0.0041) |
| 2005 | 0.9650 (0.0042) |
| 2006 | 0.9170 (0.0126) |
| 2007 | 1.0040 (0.0262) |
| 2008 | 1.0000 (0.0197) |
| 2009 | 0.9940 (0.0110) |
| 2010 | 1.0000 (0.0306) |
| 2011 | 0.9830 (0.0170) |
| 2013 | 0.9640 (0.0326) |
| 2014 | 1.0120 (0.0288) |
| 2015 | 0.8600 (0.0449) |
| 2016 | 0.9780 (0.0162) |
| 2019 | 0.9650 (0.0269) |
| 2022 | 0.9330 (0.0235) |
| 2023 | 0.9430 (0.0286) |
