| Year | Value (SE) |
|---|---|
| 2011 | 0.7220 (0.1162) |
| 2012 | 0.5370 (0.0941) |
| 2013 | 0.5750 (0.1165) |
| 2014 | 0.2900 (0.0522) |
| 2015 | 0.2910 (0.0445) |
| 2016 | 0.2280 (0.0396) |
| 2017 | 0.4110 (0.0427) |
| 2018 | 0.4070 (0.0493) |
| 2019 | 0.2230 (0.0439) |
| 2020 | 0.4410 (0.0512) |
| 2021 | 0.5030 (0.1850) |
| 2022 | 0.7980 (0.3419) |
| 2023 | 0.3100 (0.0570) |
