| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | 50.4868 |
| 2021 | 50.4621 |
| 2020 | 50.4366 |
| 2019 | 50.437 |
| 2018 | 50.4612 |
| 2017 | 50.4893 |
| 2016 | 50.5225 |
| 2015 | 50.5577 |
| 2014 | 50.5941 |
| 2013 | 50.6341 |
| 2012 | 50.6772 |
| 2011 | 50.7228 |
| 2010 | 50.7451 |
| 2009 | 50.7414 |
| 2008 | 50.7376 |
| 2007 | 50.7348 |
| 2006 | 50.7352 |
| 2005 | 50.7404 |
| 2004 | 50.7486 |
| 2003 | 50.7543 |
| 2002 | 50.751 |
| 2001 | 50.7514 |
| 2000 | 50.7692 |
| 1999 | 50.8019 |
| 1998 | 50.8372 |
| 1997 | 50.8652 |
| 1996 | 50.8883 |
| 1995 | 50.9113 |
| 1994 | 50.9347 |
| 1993 | 50.9567 |
| 1992 | 50.9821 |
| 1991 | 51.0137 |
| 1990 | 51.0442 |
| 1989 | 51.0727 |
| 1988 | 51.0991 |
| 1987 | 51.12 |
| 1986 | 51.1406 |
| 1985 | 51.1637 |
| 1984 | 51.1847 |
| 1983 | 51.2035 |
| 1982 | 51.2175 |
| 1981 | 51.2247 |
| 1980 | 51.2239 |
| 1979 | 51.2131 |
| 1978 | 51.1927 |
| 1977 | 51.1653 |
| 1976 | 51.1399 |
| 1975 | 51.1161 |
| 1974 | 51.093 |
| 1973 | 51.0734 |
| 1972 | 51.0655 |
| 1971 | 51.0766 |
| 1970 | 51.1002 |
| 1969 | 51.1069 |
| 1968 | 51.0692 |
| 1967 | 50.979 |
| 1966 | 50.8525 |
| 1965 | 50.7353 |
| 1964 | 50.6574 |
| 1963 | 50.6042 |
| 1962 | 50.5494 |
| 1961 | 50.4911 |
| 1960 | 50.4387 |