年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | 79.3 |
2020 | 79.9 |
2019 | 81.4 |
2018 | 81.2 |
2017 | 81.1 |
2016 | 81.1 |
2015 | 81.2 |
2014 | 81.3 |
2013 | 81.2 |
2012 | 81.2 |
2011 | 81.1 |
2010 | 81 |
2009 | 80.9 |
2008 | 80.6 |
2007 | 80.6 |
2006 | 80.3 |
2005 | 80.1 |
2004 | 80.1 |
2003 | 79.7 |
2002 | 79.6 |
2001 | 79.5 |
2000 | 79.3 |
1999 | 79.4 |
1998 | 79.5 |
1997 | 79.4 |
1996 | 79.1 |
1995 | 78.9 |
1994 | 79 |
1993 | 78.8 |
1992 | 79.1 |
1991 | 78.9 |
1990 | 78.8 |
1989 | 78.5 |
1988 | 78.3 |
1987 | 78.3 |
1986 | 78.2 |
1985 | 78.2 |
1984 | 78.2 |
1983 | 78.1 |
1982 | 78.1 |
1981 | 77.8 |
1980 | 77.4 |
1979 | 77.8 |
1978 | 77.3 |
1977 | 77.2 |
1976 | 76.8 |
1975 | 76.6 |
1974 | 75.9 |
1973 | 75.3 |
1972 | 75.1 |
1971 | 75 |
1970 | 74.7 |
1969 | 74.4 |
1968 | 74.1 |
1967 | 74.3 |
1966 | 73.9 |
1965 | 73.8 |
1964 | 73.7 |
1963 | 73.4 |
1962 | 73.5 |
1961 | 73.6 |
1960 | 73.1 |