| Year | Value (SE) |
|---|---|
| 2004 | 1.0580 (0.3261) |
| 2010 | 0.9590 (0.2092) |
| 2011 | 0.8980 (0.3355) |
| 2012 | 0.8140 (0.1261) |
| 2013 | 0.7820 (0.1638) |
| 2014 | 0.7220 (0.1448) |
| 2015 | 1.1500 (0.6567) |
| 2016 | 0.7190 (0.0876) |
| 2019 | 1.0980 (0.2456) |
| 2020 | 0.9000 (0.2430) |
| 2022 | 0.3590 (0.2813) |
| 2023 | 0.8770 (0.4797) |
