年份 | 美国 |
---|---|
2023 | - |
2022 | - |
2021 | 25.4814 |
2020 | 23.3838 |
2019 | 26.452 |
2018 | 27.6104 |
2017 | 27.2792 |
2016 | 26.587 |
2015 | 27.8122 |
2014 | 29.998 |
2013 | 30.0024 |
2012 | 30.6818 |
2011 | 30.8425 |
2010 | 28.2199 |
2009 | 24.7595 |
2008 | 29.8678 |
2007 | 28.012 |
2006 | 26.9753 |
2005 | 25.6386 |
2004 | 24.4481 |
2003 | 22.6273 |
2002 | 22.2864 |
2001 | 22.9672 |
2000 | 25.103 |
1999 | 23.3136 |
1998 | 22.8259 |
1997 | 23.4283 |
1996 | 22.6871 |
1995 | 22.4534 |
1994 | 21.0555 |
1993 | 20.0446 |
1992 | 19.9506 |
1991 | 19.7864 |
1990 | 19.8151 |
1989 | 19.4151 |
1988 | 19.0701 |
1987 | 17.9736 |
1986 | 16.898 |
1985 | 16.6039 |
1984 | 17.5224 |
1983 | 16.6656 |
1982 | 17.5368 |
1981 | 19.4259 |
1980 | 20.1098 |
1979 | 18.3762 |
1978 | 16.9728 |
1977 | 16.4179 |
1976 | 16.0488 |
1975 | 15.5164 |
1974 | 16.445 |
1973 | 13.0792 |
1972 | 11.3406 |
1971 | 10.7572 |
1970 | 10.7583 |
1969 | - |
1968 | - |
1967 | - |
1966 | - |
1965 | - |
1964 | - |
1963 | - |
1962 | - |
1961 | - |
1960 | - |