| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | - |
| 2021 | 75.3835 |
| 2020 | 77.1137 |
| 2019 | 79.9772 |
| 2018 | 79.9317 |
| 2017 | 79.7792 |
| 2016 | 79.8487 |
| 2015 | 80.2513 |
| 2014 | 80.5504 |
| 2013 | 80.6649 |
| 2012 | 80.7255 |
| 2011 | 80.711 |
| 2010 | 80.7062 |
| 2009 | 80.2902 |
| 2008 | 79.9626 |
| 2007 | 79.7527 |
| 2006 | 79.4065 |
| 2005 | 79.1109 |
| 2004 | 79.2138 |
| 2003 | 78.6746 |
| 2002 | 78.5378 |
| 2001 | 78.5079 |
| 2000 | 78.3778 |
| 1999 | 78.1321 |
| 1998 | 77.8888 |
| 1997 | 77.3617 |
| 1996 | 76.2946 |
| 1995 | 75.3462 |
| 1994 | 74.9842 |
| 1993 | 74.7314 |
| 1992 | 74.8833 |
| 1991 | 74.4141 |
| 1990 | 74.107 |
| 1989 | 73.6323 |
| 1988 | 73.2577 |
| 1987 | 73.1794 |
| 1986 | 72.91 |
| 1985 | 72.7065 |
| 1984 | 72.6751 |
| 1983 | 72.4409 |
| 1982 | 72.0303 |
| 1981 | 71.224 |
| 1980 | 70.5195 |
| 1979 | 70.3453 |
| 1978 | 69.565 |
| 1977 | 69.1128 |
| 1976 | 68.4409 |
| 1975 | 67.7371 |
| 1974 | 66.7411 |
| 1973 | 65.5773 |
| 1972 | 65.0307 |
| 1971 | 65.0228 |
| 1970 | 64.2318 |
| 1969 | 63.8413 |
| 1968 | 63.3322 |
| 1967 | 64.072 |
| 1966 | 63.6328 |
| 1965 | 63.8742 |
| 1964 | 63.9001 |
| 1963 | 63.7341 |
| 1962 | 64.2507 |
| 1961 | 64.6059 |
| 1960 | 63.7633 |