| Year | Value (SE) |
|---|---|
| 2000 | 0.5471 (0.1292) |
| 2006 | 0.9524 (0.1191) |
| 2008 | 0.7601 (0.0478) |
| 2009 | 0.7856 (0.0593) |
| 2010 | 0.7385 (0.0580) |
| 2011 | 0.8268 (0.0378) |
| 2012 | 0.4427 (0.1687) |
| 2013 | 0.7419 (0.0408) |
| 2014 | 0.8573 (0.0539) |
| 2016 | 0.7375 (0.0361) |
| 2017 | 0.6984 (0.0410) |
| 2018 | 0.6523 (0.0490) |
| 2019 | 0.4965 (0.0412) |
| 2020 | 0.3448 (0.0576) |
| 2021 | 0.9958 (0.3861) |
| 2022 | 0.8068 (0.2894) |
| 2023 | 0.4228 (0.1447) |
| 2024 | 0.2602 (0.0521) |
