| Year | Value (SE) |
|---|---|
| 2000 | 1.2590 (0.1018) |
| 2001 | 0.9490 (0.0080) |
| 2002 | 0.9470 (0.0259) |
| 2003 | 0.9690 (0.0426) |
| 2004 | 0.9240 (0.0178) |
| 2005 | 0.9360 (0.0139) |
| 2006 | 0.9070 (0.0283) |
| 2007 | 0.9330 (0.0367) |
| 2008 | 0.9130 (0.0270) |
| 2009 | 0.9980 (0.0310) |
| 2010 | 0.8790 (0.0648) |
| 2011 | 0.9330 (0.0365) |
| 2012 | 0.8370 (0.0279) |
| 2013 | 0.8960 (0.0472) |
| 2014 | 1.0360 (0.0402) |
| 2015 | 1.0360 (0.1227) |
| 2016 | 1.0180 (0.0298) |
| 2019 | 1.0020 (0.0727) |
| 2020 | 0.7780 (0.0717) |
| 2021 | 1.0170 (0.4751) |
| 2022 | 0.7490 (0.0951) |
| 2023 | 1.0780 (0.0853) |
