年份 | 美国 |
---|---|
2023 | - |
2022 | 3.48109 |
2021 | 3.24723 |
2020 | 3.08981 |
2019 | 3.01621 |
2018 | 2.91639 |
2017 | 2.81075 |
2016 | 2.74782 |
2015 | 2.70253 |
2014 | 2.65694 |
2013 | 2.62675 |
2012 | 2.60788 |
2011 | 2.59559 |
2010 | 2.58943 |
2009 | 2.62382 |
2008 | 2.66419 |
2007 | 2.69995 |
2006 | 2.76339 |
2005 | 2.81337 |
2004 | 2.81649 |
2003 | 2.88269 |
2002 | 2.96623 |
2001 | 2.95911 |
2000 | 2.9772 |
1999 | 3.04245 |
1998 | 3.00341 |
1997 | 2.92177 |
1996 | 2.91204 |
1995 | 2.88665 |
1994 | 2.83697 |
1993 | 2.83432 |
1992 | 2.88178 |
1991 | 2.91632 |
1990 | 2.93275 |
1989 | 2.93493 |
1988 | 2.92219 |
1987 | 2.89062 |
1986 | 2.81936 |
1985 | 2.75518 |
1984 | 2.71281 |
1983 | 2.64978 |
1982 | 2.60604 |
1981 | 2.5837 |
1980 | 2.53582 |
1979 | 2.49295 |
1978 | 2.48672 |
1977 | 2.45767 |
1976 | 2.4149 |
1975 | 2.39824 |
1974 | 2.3703 |
1973 | 2.31366 |
1972 | 2.24675 |
1971 | 2.1979 |
1970 | 2.16032 |
1969 | 2.1304 |
1968 | 2.12022 |
1967 | 2.1188 |
1966 | 2.0943 |
1965 | 2.05378 |
1964 | 2.01815 |
1963 | 1.98543 |
1962 | 1.95507 |
1961 | 1.92324 |
1960 | 1.88628 |