| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | - |
| 2021 | 85.2376 |
| 2020 | 86.4501 |
| 2019 | 87.7998 |
| 2018 | 87.7357 |
| 2017 | 87.5552 |
| 2016 | 87.5474 |
| 2015 | 87.7551 |
| 2014 | 87.8868 |
| 2013 | 88.0417 |
| 2012 | 88.0813 |
| 2011 | 88.0285 |
| 2010 | 88.0664 |
| 2009 | 87.7544 |
| 2008 | 87.6493 |
| 2007 | 87.5469 |
| 2006 | 87.2715 |
| 2005 | 87.0998 |
| 2004 | 87.0536 |
| 2003 | 86.6991 |
| 2002 | 86.6593 |
| 2001 | 86.5467 |
| 2000 | 86.5156 |
| 1999 | 86.4085 |
| 1998 | 86.3939 |
| 1997 | 86.1221 |
| 1996 | 85.8616 |
| 1995 | 85.5942 |
| 1994 | 85.5422 |
| 1993 | 85.3884 |
| 1992 | 85.5518 |
| 1991 | 85.2667 |
| 1990 | 85.1451 |
| 1989 | 84.859 |
| 1988 | 84.554 |
| 1987 | 84.5836 |
| 1986 | 84.4712 |
| 1985 | 84.3355 |
| 1984 | 84.2674 |
| 1983 | 84.1344 |
| 1982 | 84.0674 |
| 1981 | 83.7011 |
| 1980 | 83.4124 |
| 1979 | 83.4836 |
| 1978 | 82.9008 |
| 1977 | 82.6652 |
| 1976 | 82.2644 |
| 1975 | 81.939 |
| 1974 | 81.2697 |
| 1973 | 80.5773 |
| 1972 | 80.3556 |
| 1971 | 80.0638 |
| 1970 | 79.6218 |
| 1969 | 79.4853 |
| 1968 | 79.0302 |
| 1967 | 79.4489 |
| 1966 | 79.0844 |
| 1965 | 78.9058 |
| 1964 | 78.6788 |
| 1963 | 78.3985 |
| 1962 | 78.6145 |
| 1961 | 78.8423 |
| 1960 | 78.2174 |