| Year | Value (SE) |
|---|---|
| 2000 | 0.6093 (0.0498) |
| 2001 | 0.5655 (0.0216) |
| 2008 | 0.9442 (0.0387) |
| 2009 | 0.9288 (0.0179) |
| 2010 | 0.8733 (0.0397) |
| 2011 | 0.8793 (0.0136) |
| 2012 | 0.9330 (0.0201) |
| 2013 | 1.1246 (0.0864) |
| 2014 | 1.1088 (0.0641) |
| 2015 | 0.8010 (0.1399) |
| 2016 | 0.9194 (0.0333) |
| 2017 | 0.9099 (0.0216) |
| 2018 | 0.9387 (0.0299) |
| 2019 | 0.8937 (0.0208) |
| 2020 | 1.0814 (0.1913) |
| 2021 | 1.6233 (0.6722) |
| 2022 | 1.0871 (0.2885) |
| 2023 | 0.8683 (0.0971) |
