| Year | Value (SE) |
|---|---|
| 2009 | 0.8600 (0.0468) |
| 2010 | 0.8940 (0.1383) |
| 2011 | 0.9660 (0.0245) |
| 2012 | 0.9720 (0.0419) |
| 2013 | 0.8900 (0.1002) |
| 2014 | 0.8340 (0.0636) |
| 2015 | 1.0530 (0.2545) |
| 2016 | 0.7640 (0.0408) |
| 2018 | 0.9430 (0.0579) |
| 2019 | 1.0590 (0.0369) |
| 2022 | 1.2150 (0.4404) |
| 2023 | 1.1050 (0.1415) |
| 2024 | 0.5150 (0.1674) |
