| Year | Value (SE) |
|---|---|
| 2004 | 0.6730 (0.0724) |
| 2010 | 0.8919 (0.1614) |
| 2011 | 0.7605 (0.1273) |
| 2012 | 0.8443 (0.0894) |
| 2013 | 0.7351 (0.1251) |
| 2014 | 0.7842 (0.1053) |
| 2015 | 0.8260 (0.3167) |
| 2016 | 0.7239 (0.0499) |
| 2019 | 0.5402 (0.0916) |
| 2020 | 0.7818 (0.2407) |
| 2022 | 1.5735 (1.1512) |
| 2023 | 1.1496 (0.5130) |
