| Year | Value (SE) |
|---|---|
| 2003 | 0.9870 (0.1147) |
| 2004 | 0.5990 (0.1097) |
| 2005 | 0.7610 (0.0998) |
| 2006 | 0.8620 (0.1238) |
| 2008 | 0.9320 (0.2295) |
| 2009 | 1.1970 (0.2910) |
| 2010 | 0.5870 (0.1160) |
| 2011 | 0.8270 (0.2096) |
| 2013 | 0.7920 (0.1561) |
| 2014 | 0.7450 (0.1708) |
| 2015 | 0.6280 (0.2714) |
| 2019 | 0.5980 (0.1775) |
| 2020 | 0.3120 (0.2129) |
| 2023 | 0.8380 (0.5050) |
