| Year | Value (SE) |
|---|---|
| 2006 | 0.7395 (0.2060) |
| 2008 | 0.5501 (0.1078) |
| 2009 | 0.6524 (0.1052) |
| 2010 | 0.6565 (0.0897) |
| 2011 | 0.6409 (0.0830) |
| 2012 | 0.7587 (0.1074) |
| 2015 | 0.1116 (0.0912) |
| 2016 | 0.1279 (0.0983) |
| 2019 | 0.6203 (0.2474) |
| 2020 | 0.5959 (0.3028) |
| 2021 | 0.1991 (0.1699) |
| 2022 | 0.3494 (0.1290) |
| 2023 | 0.1121 (0.0955) |
