| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | -0.86206 |
| 2021 | -1.05616 |
| 2020 | -0.211225 |
| 2019 | -0.695262 |
| 2018 | -0.583255 |
| 2017 | -0.453842 |
| 2016 | -0.322855 |
| 2015 | -0.284256 |
| 2014 | -0.255415 |
| 2013 | -0.265051 |
| 2012 | -0.188989 |
| 2011 | -0.171767 |
| 2010 | -0.0300018 |
| 2009 | 0.0141332 |
| 2008 | 0.0856573 |
| 2007 | 0.0931571 |
| 2006 | 0.10867 |
| 2005 | 0.0733898 |
| 2004 | 0.0695994 |
| 2003 | 0.0108631 |
| 2002 | 0.0815023 |
| 2001 | 0.140998 |
| 2000 | -0.380114 |
| 1999 | -0.554086 |
| 1998 | -0.526404 |
| 1997 | -0.473417 |
| 1996 | -0.517078 |
| 1995 | -0.474899 |
| 1994 | -0.433369 |
| 1993 | -0.330624 |
| 1992 | -0.256237 |
| 1991 | -0.300544 |
| 1990 | 0.279028 |
| 1989 | 0.35604 |
| 1988 | 0.315139 |
| 1987 | 0.304464 |
| 1986 | 0.334331 |
| 1985 | 0.299754 |
| 1984 | 0.28286 |
| 1983 | 0.327097 |
| 1982 | 0.369463 |
| 1981 | 0.400952 |
| 1980 | 0.784585 |
| 1979 | 1.06557 |
| 1978 | 1.02538 |
| 1977 | 0.967796 |
| 1976 | 0.912259 |
| 1975 | 0.948037 |
| 1974 | 0.875727 |
| 1973 | 0.916558 |
| 1972 | 1.03262 |
| 1971 | 1.22265 |
| 1970 | 0.151142 |
| 1969 | -0.360009 |
| 1968 | -0.332099 |
| 1967 | -0.235016 |
| 1966 | -0.162376 |
| 1965 | -0.0604997 |
| 1964 | 0.0849372 |
| 1963 | 0.141586 |
| 1962 | 0.246911 |
| 1961 | 0.379768 |
| 1960 | - |