年份 | 美国 |
---|---|
2023 | - |
2022 | 6.83149 |
2021 | 6.81541 |
2020 | 6.80521 |
2019 | 6.79083 |
2018 | 6.75565 |
2017 | 6.69078 |
2016 | 6.59604 |
2015 | 6.48774 |
2014 | 6.40442 |
2013 | 6.36515 |
2012 | 6.37725 |
2011 | 6.47699 |
2010 | 6.66149 |
2009 | 6.85639 |
2008 | 7.01821 |
2007 | 7.13416 |
2006 | 7.18908 |
2005 | 7.22467 |
2004 | 7.318 |
2003 | 7.4813 |
2002 | 7.67387 |
2001 | 7.88667 |
2000 | 8.10194 |
1999 | 8.27368 |
1998 | 8.40302 |
1997 | 8.50593 |
1996 | 8.5699 |
1995 | 8.58433 |
1994 | 8.56666 |
1993 | 8.51686 |
1992 | 8.40118 |
1991 | 8.39992 |
1990 | 8.28604 |
1989 | 7.92564 |
1988 | 7.6691 |
1987 | 7.54708 |
1986 | 7.30796 |
1985 | 7.05363 |
1984 | 6.95239 |
1983 | 6.8368 |
1982 | 6.64411 |
1981 | 6.31611 |
1980 | 6.10967 |
1979 | 6.05834 |
1978 | 5.8969 |
1977 | 5.67629 |
1976 | 5.61648 |
1975 | 5.58648 |
1974 | 5.47949 |
1973 | 5.5073 |
1972 | 5.61649 |
1971 | 5.71502 |
1970 | 5.91193 |
1969 | 6.28243 |
1968 | 6.52769 |
1967 | 6.629 |
1966 | 6.73487 |
1965 | 6.70725 |
1964 | 6.52118 |
1963 | 6.54414 |
1962 | 6.68976 |
1961 | 6.65154 |
1960 | 6.7302 |