年份 | 美国 |
---|---|
2023 | - |
2022 | 12.3236 |
2021 | 11.4356 |
2020 | 10.3385 |
2019 | 9.95934 |
2018 | 9.98924 |
2017 | 11.5835 |
2016 | 10.9183 |
2015 | 11.2375 |
2014 | 10.9354 |
2013 | 10.4835 |
2012 | 9.76392 |
2011 | 9.53893 |
2010 | 8.56323 |
2009 | 7.90352 |
2008 | 10.2762 |
2007 | 11.2899 |
2006 | 11.3105 |
2005 | 10.6817 |
2004 | 9.53747 |
2003 | 9.3907 |
2002 | 9.86801 |
2001 | 11.8577 |
2000 | 12.9708 |
1999 | 12.26 |
1998 | 12.3298 |
1997 | 11.8282 |
1996 | 11.3739 |
1995 | 10.981 |
1994 | 10.6235 |
1993 | 10.3049 |
1992 | 9.98416 |
1991 | 10.3203 |
1990 | 10.4653 |
1989 | 10.7824 |
1988 | 10.5959 |
1987 | 10.9488 |
1986 | 10.163 |
1985 | 10.3842 |
1984 | 10.1597 |
1983 | 10.3483 |
1982 | 11.9786 |
1981 | 12.5505 |
1980 | 12.1384 |
1979 | 12.0038 |
1978 | 11.5424 |
1977 | 11.6186 |
1976 | 10.7488 |
1975 | 11.1858 |
1974 | 11.8376 |
1973 | 11.4952 |
1972 | 11.8199 |
1971 | - |
1970 | - |
1969 | - |
1968 | - |
1967 | - |
1966 | - |
1965 | - |
1964 | - |
1963 | - |
1962 | - |
1961 | - |
1960 | - |