年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | 6.2 |
2020 | 6.3 |
2019 | 6.4 |
2018 | 6.5 |
2017 | 6.6 |
2016 | 6.7 |
2015 | 6.8 |
2014 | 6.9 |
2013 | 7 |
2012 | 7.1 |
2011 | 7.2 |
2010 | 7.3 |
2009 | 7.5 |
2008 | 7.6 |
2007 | 7.7 |
2006 | 7.9 |
2005 | 8 |
2004 | 8.1 |
2003 | 8.1 |
2002 | 8.2 |
2001 | 8.3 |
2000 | 8.4 |
1999 | 8.6 |
1998 | 8.8 |
1997 | 8.9 |
1996 | 9.2 |
1995 | 9.5 |
1994 | 9.8 |
1993 | 10.1 |
1992 | 10.5 |
1991 | 10.9 |
1990 | 11.2 |
1989 | 11.6 |
1988 | 11.9 |
1987 | 12.1 |
1986 | 12.4 |
1985 | 12.7 |
1984 | 13 |
1983 | 13.4 |
1982 | 13.9 |
1981 | 14.4 |
1980 | 15 |
1979 | 15.6 |
1978 | 16.3 |
1977 | 17.1 |
1976 | 17.9 |
1975 | 18.8 |
1974 | 19.7 |
1973 | 20.6 |
1972 | 21.5 |
1971 | 22.4 |
1970 | 23.2 |
1969 | 24.1 |
1968 | 24.9 |
1967 | 25.7 |
1966 | 26.4 |
1965 | 27.1 |
1964 | 27.7 |
1963 | 28.3 |
1962 | 28.9 |
1961 | 29.5 |
1960 | 30.1 |