| Year | Value (SE) |
|---|---|
| 2000 | 0.6860 (0.0596) |
| 2001 | 0.5750 (0.0178) |
| 2002 | 0.6670 (0.0264) |
| 2010 | 0.7390 (0.0835) |
| 2011 | 0.7010 (0.0756) |
| 2012 | 0.6070 (0.0699) |
| 2013 | 0.8090 (0.0671) |
| 2014 | 0.8500 (0.1053) |
| 2015 | 0.7340 (0.0762) |
| 2016 | 0.7740 (0.0329) |
| 2017 | 0.6920 (0.0404) |
| 2018 | 0.7710 (0.0644) |
| 2019 | 0.7020 (0.0797) |
| 2020 | 0.7490 (0.0874) |
| 2021 | 0.8220 (0.1331) |
| 2022 | 0.9870 (0.4265) |
| 2023 | 0.6340 (0.1030) |
| 2024 | 0.7380 (0.1740) |
