| Year | Value (SE) |
|---|---|
| 2009 | 0.7410 (0.0833) |
| 2010 | 0.6660 (0.1148) |
| 2011 | 0.8610 (0.0767) |
| 2012 | 0.9610 (0.1155) |
| 2013 | 1.3010 (0.2476) |
| 2014 | 1.0000 (0.1532) |
| 2015 | 0.7010 (0.1555) |
| 2016 | 0.8550 (0.0796) |
| 2018 | 0.8770 (0.1434) |
| 2019 | 0.8950 (0.0933) |
| 2022 | 1.1040 (0.5393) |
| 2023 | 1.2810 (0.2788) |
| 2024 | 1.0350 (0.3767) |
