| Year | Value (SE) |
|---|---|
| 2009 | 0.5805 (0.0729) |
| 2010 | 0.5350 (0.1281) |
| 2011 | 0.5755 (0.0541) |
| 2012 | 0.7434 (0.0959) |
| 2013 | 0.8927 (0.2014) |
| 2014 | 0.9152 (0.1582) |
| 2015 | 0.5713 (0.1896) |
| 2016 | 0.5819 (0.0627) |
| 2018 | 0.6210 (0.1098) |
| 2019 | 0.6950 (0.0773) |
| 2022 | 0.6602 (0.4032) |
| 2023 | 0.6606 (0.1685) |
| 2024 | 0.4848 (0.2383) |
