| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | - |
| 2021 | 8.12243 |
| 2020 | -3.92136 |
| 2019 | 1.52267 |
| 2018 | 2.33745 |
| 2017 | 1.7383 |
| 2016 | 1.73823 |
| 2015 | 2.52185 |
| 2014 | 1.95743 |
| 2013 | 0.78693 |
| 2012 | 0.626435 |
| 2011 | 0.965065 |
| 2010 | 1.06396 |
| 2009 | -2.16692 |
| 2008 | -0.7928 |
| 2007 | 1.46136 |
| 2006 | 1.90994 |
| 2005 | 2.59143 |
| 2004 | 2.81405 |
| 2003 | 2.28133 |
| 2002 | 1.59595 |
| 2001 | 1.46713 |
| 2000 | 3.87453 |
| 1999 | 4.17789 |
| 1998 | 4.09056 |
| 1997 | 2.52371 |
| 1996 | 2.27311 |
| 1995 | 1.73186 |
| 1994 | 2.60827 |
| 1993 | 2.12799 |
| 1992 | 2.25208 |
| 1991 | -1.14925 |
| 1990 | 0.86815 |
| 1989 | 1.94826 |
| 1988 | 3.23524 |
| 1987 | 2.47513 |
| 1986 | 3.17024 |
| 1985 | 4.24961 |
| 1984 | 4.35334 |
| 1983 | 4.69934 |
| 1982 | 0.50114 |
| 1981 | 0.396429 |
| 1980 | -1.26421 |
| 1979 | 1.25339 |
| 1978 | 3.27633 |
| 1977 | 3.1834 |
| 1976 | 4.575 |
| 1975 | 1.26403 |
| 1974 | -1.73956 |
| 1973 | 3.95187 |
| 1972 | 4.99479 |
| 1971 | 2.51452 |
| 1970 | - |
| 1969 | - |
| 1968 | - |
| 1967 | - |
| 1966 | - |
| 1965 | - |
| 1964 | - |
| 1963 | - |
| 1962 | - |
| 1961 | - |
| 1960 | - |