| Year | Value (SE) |
|---|---|
| 2012 | 0.8324 (0.0726) |
| 2013 | 0.7287 (0.0815) |
| 2014 | 0.7472 (0.0597) |
| 2015 | 0.8140 (0.1729) |
| 2016 | 0.7683 (0.0575) |
| 2017 | 0.8055 (0.0637) |
| 2018 | 0.8362 (0.1002) |
| 2019 | 0.7521 (0.0608) |
| 2020 | 1.0460 (0.2684) |
| 2021 | 0.9868 (0.4238) |
| 2022 | 0.6798 (0.2051) |
| 2023 | 0.5500 (0.1079) |
| 2024 | 0.7572 (0.3423) |
