| Year | Value (SE) |
|---|---|
| 2009 | 0.7680 (0.0684) |
| 2010 | 0.8600 (0.1664) |
| 2011 | 0.6955 (0.0351) |
| 2012 | 0.7591 (0.0649) |
| 2013 | 0.7254 (0.1051) |
| 2014 | 0.8373 (0.0936) |
| 2015 | 0.7624 (0.2022) |
| 2016 | 0.6647 (0.0557) |
| 2018 | 0.6808 (0.1008) |
| 2019 | 0.7932 (0.0643) |
| 2022 | 0.7266 (0.3655) |
| 2023 | 0.5724 (0.1306) |
| 2024 | 0.5037 (0.1995) |
