年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | 73.5 |
2020 | 74.2 |
2019 | 76.3 |
2018 | 76.2 |
2017 | 76.1 |
2016 | 76.1 |
2015 | 76.3 |
2014 | 76.5 |
2013 | 76.4 |
2012 | 76.4 |
2011 | 76.3 |
2010 | 76.2 |
2009 | 76 |
2008 | 75.6 |
2007 | 75.5 |
2006 | 75.2 |
2005 | 75 |
2004 | 75 |
2003 | 74.5 |
2002 | 74.4 |
2001 | 74.3 |
2000 | 74.1 |
1999 | 73.9 |
1998 | 73.8 |
1997 | 73.6 |
1996 | 73.1 |
1995 | 72.5 |
1994 | 72.4 |
1993 | 72.2 |
1992 | 72.3 |
1991 | 72 |
1990 | 71.8 |
1989 | 71.7 |
1988 | 71.4 |
1987 | 71.4 |
1986 | 71.2 |
1985 | 71.1 |
1984 | 71.1 |
1983 | 71 |
1982 | 70.8 |
1981 | 70.4 |
1980 | 70 |
1979 | 70 |
1978 | 69.6 |
1977 | 69.5 |
1976 | 69.1 |
1975 | 68.8 |
1974 | 68.2 |
1973 | 67.6 |
1972 | 67.4 |
1971 | 67.4 |
1970 | 67.1 |
1969 | 66.8 |
1968 | 66 |
1967 | 67 |
1966 | 66.7 |
1965 | 66.8 |
1964 | 66.8 |
1963 | 66.6 |
1962 | 66.9 |
1961 | 67.1 |
1960 | 66.6 |