| Year | Value (SE) |
|---|---|
| 2000 | 0.6494 (0.0375) |
| 2001 | 0.5753 (0.0102) |
| 2008 | 0.7859 (0.0154) |
| 2009 | 0.8436 (0.0095) |
| 2010 | 0.7590 (0.0168) |
| 2011 | 0.7667 (0.0069) |
| 2012 | 0.7318 (0.0090) |
| 2013 | 0.7395 (0.0284) |
| 2014 | 0.8908 (0.0209) |
| 2015 | 0.7579 (0.0676) |
| 2016 | 0.7019 (0.0152) |
| 2017 | 0.7124 (0.0096) |
| 2018 | 0.7729 (0.0136) |
| 2019 | 0.7688 (0.0096) |
| 2020 | 0.7188 (0.0471) |
| 2021 | 1.1293 (0.1847) |
| 2022 | 0.6463 (0.0584) |
| 2023 | 0.6988 (0.0448) |
