| Year | Value (SE) |
|---|---|
| 2000 | 0.8530 (0.1478) |
| 2001 | 0.2530 (0.0187) |
| 2008 | 0.7860 (0.0356) |
| 2009 | 0.8160 (0.0264) |
| 2010 | 0.8370 (0.0376) |
| 2011 | 0.7190 (0.0196) |
| 2012 | 0.8280 (0.0322) |
| 2013 | 0.6220 (0.0484) |
| 2014 | 0.7290 (0.0545) |
| 2015 | 1.1190 (0.1891) |
| 2016 | 0.8760 (0.0382) |
| 2017 | 0.8470 (0.0385) |
| 2018 | 0.7350 (0.0568) |
| 2019 | 0.6870 (0.0375) |
| 2020 | 0.6280 (0.1240) |
| 2021 | 0.5440 (0.2141) |
| 2022 | 0.7520 (0.2443) |
| 2023 | 0.9330 (0.1349) |
