年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | - |
2020 | 12.6542 |
2019 | 15.5171 |
2018 | 15.7807 |
2017 | 15.9008 |
2016 | 15.9738 |
2015 | 16.0525 |
2014 | 16.0046 |
2013 | 16.0246 |
2012 | 15.5992 |
2011 | 15.5075 |
2010 | 15.5617 |
2009 | 15.6011 |
2008 | 16.2201 |
2007 | 16.7058 |
2006 | 16.8092 |
2005 | 16.6988 |
2004 | 16.962 |
2003 | 16.9816 |
2002 | 17.3132 |
2001 | 17.6896 |
2000 | 17.9882 |
1999 | 17.555 |
1998 | 17.1347 |
1997 | 16.612 |
1996 | 16.1 |
1995 | 15.8899 |
1994 | 15.5527 |
1993 | 15.2749 |
1992 | 15.1028 |
1991 | 15.3581 |
1990 | 15.2107 |
1989 | 15.1974 |
1988 | 14.8521 |
1987 | 14.4409 |
1986 | 14.2158 |
1985 | 14.0242 |
1984 | 14.0671 |
1983 | 13.9664 |
1982 | 14.2721 |
1981 | 14.8959 |
1980 | 15.5544 |
1979 | 16.3265 |
1978 | 16.5371 |
1977 | 16.9861 |
1976 | 17.3518 |
1975 | 17.3917 |
1974 | 17.6381 |
1973 | 17.7788 |
1972 | 17.4885 |
1971 | - |
1970 | - |
1969 | - |
1968 | - |
1967 | - |
1966 | - |
1965 | - |
1964 | - |
1963 | - |
1962 | - |
1961 | - |
1960 | - |