年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | 14.5887 |
2020 | 13.1816 |
2019 | 14.5795 |
2018 | 15.2494 |
2017 | 15.0174 |
2016 | 14.6475 |
2015 | 15.3512 |
2014 | 16.452 |
2013 | 16.4243 |
2012 | 17.0378 |
2011 | 17.279 |
2010 | 15.8785 |
2009 | 13.8273 |
2008 | 17.4419 |
2007 | 16.5482 |
2006 | 16.3339 |
2005 | 15.6565 |
2004 | 14.8193 |
2003 | 13.5917 |
2002 | 13.155 |
2001 | 13.2637 |
2000 | 14.4102 |
1999 | 13.0042 |
1998 | 12.3106 |
1997 | 12.3086 |
1996 | 11.9404 |
1995 | 11.8142 |
1994 | 11.1623 |
1993 | 10.4974 |
1992 | 10.2417 |
1991 | 10.1255 |
1990 | 10.5603 |
1989 | 10.4763 |
1988 | 10.5796 |
1987 | 10.4777 |
1986 | 9.88872 |
1985 | 9.61583 |
1984 | 10.0333 |
1983 | 9.04333 |
1982 | 9.06708 |
1981 | 9.90814 |
1980 | 10.2834 |
1979 | 9.61713 |
1978 | 9.02577 |
1977 | 8.76361 |
1976 | 8.06795 |
1975 | 7.28409 |
1974 | 8.24886 |
1973 | 6.39544 |
1972 | 5.80216 |
1971 | 5.35193 |
1970 | 5.19518 |
1969 | - |
1968 | - |
1967 | - |
1966 | - |
1965 | - |
1964 | - |
1963 | - |
1962 | - |
1961 | - |
1960 | - |