| Year | Value (SE) |
|---|---|
| 2009 | 0.8772 (0.0469) |
| 2010 | 0.8350 (0.1370) |
| 2011 | 0.9283 (0.0252) |
| 2012 | 0.9905 (0.0447) |
| 2013 | 0.8419 (0.1008) |
| 2014 | 0.9116 (0.0713) |
| 2015 | 1.1257 (0.2763) |
| 2016 | 0.7823 (0.0409) |
| 2018 | 0.9807 (0.0617) |
| 2019 | 1.0368 (0.0365) |
| 2022 | 0.9999 (0.3604) |
| 2023 | 0.9956 (0.1270) |
| 2024 | 0.4789 (0.1569) |
