| Year | Value (SE) |
|---|---|
| 2004 | 0.4100 (0.1231) |
| 2010 | 0.6020 (0.1243) |
| 2011 | 0.4460 (0.1543) |
| 2012 | 0.5240 (0.0692) |
| 2013 | 0.3190 (0.0612) |
| 2014 | 0.3920 (0.0687) |
| 2015 | 0.6000 (0.3250) |
| 2016 | 0.3970 (0.0441) |
| 2019 | 0.3290 (0.0613) |
| 2020 | 0.4340 (0.0776) |
| 2022 | 0.3520 (0.1334) |
| 2023 | 0.4520 (0.1598) |
