年份 | 美国 |
---|---|
2023 | - |
2022 | 6.11236 |
2021 | 6.24197 |
2020 | 6.34398 |
2019 | 6.39514 |
2018 | 6.4008 |
2017 | 6.37667 |
2016 | 6.34711 |
2015 | 6.35047 |
2014 | 6.373 |
2013 | 6.39026 |
2012 | 6.4125 |
2011 | 6.44075 |
2010 | 6.47245 |
2009 | 6.52164 |
2008 | 6.59696 |
2007 | 6.69941 |
2006 | 6.82004 |
2005 | 6.94037 |
2004 | 7.03881 |
2003 | 7.08981 |
2002 | 7.08777 |
2001 | 7.05147 |
2000 | 6.99871 |
1999 | 6.93457 |
1998 | 6.88106 |
1997 | 6.85347 |
1996 | 6.84649 |
1995 | 6.85173 |
1994 | 6.86128 |
1993 | 6.84956 |
1992 | 6.79683 |
1991 | 6.70855 |
1990 | 6.60338 |
1989 | 6.51939 |
1988 | 6.47578 |
1987 | 6.49189 |
1986 | 6.61551 |
1985 | 6.83769 |
1984 | 7.06345 |
1983 | 7.26557 |
1982 | 7.44834 |
1981 | 7.57075 |
1980 | 7.67657 |
1979 | 7.86698 |
1978 | 8.15231 |
1977 | 8.4851 |
1976 | 8.82851 |
1975 | 9.14069 |
1974 | 9.36626 |
1973 | 9.51421 |
1972 | 9.63554 |
1971 | 9.71739 |
1970 | 9.74954 |
1969 | 9.7537 |
1968 | 9.72642 |
1967 | 9.64041 |
1966 | 9.68438 |
1965 | 9.62228 |
1964 | 9.27402 |
1963 | 9.05482 |
1962 | 9.09303 |
1961 | 9.01376 |
1960 | 8.83181 |