| Year | Value (SE) |
|---|---|
| 2000 | 0.6860 (0.0914) |
| 2001 | 0.8070 (0.0499) |
| 2002 | 0.9470 (0.0715) |
| 2003 | 1.0030 (0.1002) |
| 2004 | 0.7210 (0.0967) |
| 2007 | 0.8450 (0.0458) |
| 2011 | 1.1280 (0.1741) |
| 2012 | 0.8650 (0.0782) |
| 2013 | 0.9230 (0.1162) |
| 2014 | 0.7910 (0.0827) |
| 2015 | 0.7600 (0.1215) |
| 2016 | 0.8430 (0.0724) |
| 2017 | 0.8110 (0.1043) |
| 2018 | 0.8880 (0.0651) |
| 2022 | 0.9880 (0.5681) |
| 2023 | 0.6330 (0.1446) |
| 2024 | 1.0000 (0.2889) |
