| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | 57.7249 |
| 2021 | 55.6616 |
| 2020 | 52.8424 |
| 2019 | 52.0242 |
| 2018 | 51.6424 |
| 2017 | 49.5827 |
| 2016 | 54.019 |
| 2015 | 54.1975 |
| 2014 | 53.0964 |
| 2013 | 51.1738 |
| 2012 | 53.5348 |
| 2011 | 52.7837 |
| 2010 | 47.6567 |
| 2009 | 45.4913 |
| 2008 | 53.3187 |
| 2007 | 56.0075 |
| 2006 | 55.7544 |
| 2005 | 54.2419 |
| 2004 | 50.7852 |
| 2003 | 50.1184 |
| 2002 | 50.8492 |
| 2001 | 55.2814 |
| 2000 | 57.4623 |
| 1999 | 55.8588 |
| 1998 | 56.6081 |
| 1997 | 55.2567 |
| 1996 | 54.1512 |
| 1995 | 52.0937 |
| 1994 | 51.3871 |
| 1993 | 50.6912 |
| 1992 | 49.9239 |
| 1991 | 48.8169 |
| 1990 | 51.635 |
| 1989 | 52.4887 |
| 1988 | 51.4924 |
| 1987 | 52.3972 |
| 1986 | 50.0942 |
| 1985 | 50.0474 |
| 1984 | 49.4947 |
| 1983 | 49.9112 |
| 1982 | 52.6705 |
| 1981 | 54.2022 |
| 1980 | 56.5582 |
| 1979 | 58.039 |
| 1978 | 57.8606 |
| 1977 | 57.0117 |
| 1976 | 55.6388 |
| 1975 | 55.9202 |
| 1974 | 56.7827 |
| 1973 | 57.1739 |
| 1972 | 59.3576 |
| 1971 | - |
| 1970 | - |
| 1969 | - |
| 1968 | - |
| 1967 | - |
| 1966 | - |
| 1965 | - |
| 1964 | - |
| 1963 | - |
| 1962 | - |
| 1961 | - |
| 1960 | - |