| Year | Value (SE) |
|---|---|
| 2006 | 0.8064 (0.1284) |
| 2008 | 0.7080 (0.1013) |
| 2009 | 0.7986 (0.0758) |
| 2010 | 0.9055 (0.0709) |
| 2011 | 0.9065 (0.0794) |
| 2012 | 0.9011 (0.0954) |
| 2015 | 0.1934 (0.1243) |
| 2016 | 0.3533 (0.2369) |
| 2019 | 0.9572 (0.3151) |
| 2020 | 0.6764 (0.2659) |
| 2021 | 0.1667 (0.1205) |
| 2022 | 0.5983 (0.1620) |
| 2023 | 0.4769 (0.3464) |
