年份 | 美国 |
---|---|
2023 | - |
2022 | 27.6672 |
2021 | 28.0325 |
2020 | 28.3633 |
2019 | 28.6165 |
2018 | 28.7877 |
2017 | 28.9262 |
2016 | 28.9844 |
2015 | 29.0729 |
2014 | 29.234 |
2013 | 29.3471 |
2012 | 29.4163 |
2011 | 29.4745 |
2010 | 29.6057 |
2009 | 29.8 |
2008 | 29.9668 |
2007 | 30.1445 |
2006 | 30.405 |
2005 | 30.7493 |
2004 | 31.1239 |
2003 | 31.4589 |
2002 | 31.7547 |
2001 | 32.0477 |
2000 | 32.3368 |
1999 | 32.5757 |
1998 | 32.737 |
1997 | 32.8815 |
1996 | 33.0452 |
1995 | 33.2082 |
1994 | 33.2965 |
1993 | 33.2632 |
1992 | 33.1129 |
1991 | 32.8597 |
1990 | 32.5832 |
1989 | 32.3508 |
1988 | 32.1236 |
1987 | 31.9707 |
1986 | 32.0441 |
1985 | 32.3023 |
1984 | 32.5857 |
1983 | 32.8746 |
1982 | 33.1749 |
1981 | 33.4793 |
1980 | 33.9215 |
1979 | 34.5845 |
1978 | 35.4618 |
1977 | 36.4884 |
1976 | 37.6548 |
1975 | 38.9688 |
1974 | 40.3203 |
1973 | 41.7057 |
1972 | 43.1422 |
1971 | 44.4903 |
1970 | 45.6832 |
1969 | 46.8245 |
1968 | 47.9957 |
1967 | 49.0182 |
1966 | 50.2824 |
1965 | 51.0826 |
1964 | 50.9526 |
1963 | 50.9798 |
1962 | 51.3489 |
1961 | 51.7115 |
1960 | 51.3974 |