Data Table
| Year | Value (SE) |
| 2000 | 0.7804 (0.0528) |
| 2001 | 0.5743 (0.0075) |
| 2002 | 0.7845 (0.0066) |
| 2003 | 0.7812 (0.0256) |
| 2005 | 0.7739 (0.0230) |
| 2006 | 0.7707 (0.0139) |
| 2007 | 0.8218 (0.0139) |
| 2008 | 0.7657 (0.0446) |
| 2009 | 0.8730 (0.0281) |
| 2010 | 0.8489 (0.0639) |
| 2011 | 0.7032 (0.0263) |
| 2012 | 0.9054 (0.0312) |
| 2013 | 0.9628 (0.0551) |
| 2014 | 0.8438 (0.0422) |
| 2015 | 0.8833 (0.0866) |
| 2016 | 0.7751 (0.0281) |
| 2017 | 0.8070 (0.0461) |
| 2018 | 0.7638 (0.0519) |
| 2019 | 0.8909 (0.0709) |
| 2020 | 0.6909 (0.1263) |
| 2021 | 0.8175 (0.3609) |
| 2022 | 0.7688 (0.1810) |
| 2023 | 0.7088 (0.0977) |
| 2024 | 0.6278 (0.2744) |