年份 | 美国 |
---|---|
2023 | - |
2022 | 2.91013 |
2021 | 2.71167 |
2020 | 2.57217 |
2019 | 2.52678 |
2018 | 2.44264 |
2017 | 2.34575 |
2016 | 2.30744 |
2015 | 2.27609 |
2014 | 2.21627 |
2013 | 2.19451 |
2012 | 2.19958 |
2011 | 2.20255 |
2010 | 2.23152 |
2009 | 2.31889 |
2008 | 2.37295 |
2007 | 2.38904 |
2006 | 2.40113 |
2005 | 2.35431 |
2004 | 2.24891 |
2003 | 2.19888 |
2002 | 2.1928 |
2001 | 2.14536 |
2000 | 2.14361 |
1999 | 2.19718 |
1998 | 2.16747 |
1997 | 2.09059 |
1996 | 2.06683 |
1995 | 2.03099 |
1994 | 1.96994 |
1993 | 1.94035 |
1992 | 1.95655 |
1991 | 1.9618 |
1990 | 1.95393 |
1989 | 1.94308 |
1988 | 1.92734 |
1987 | 1.90412 |
1986 | 1.85662 |
1985 | 1.81453 |
1984 | 1.78928 |
1983 | 1.74663 |
1982 | 1.71297 |
1981 | 1.6934 |
1980 | 1.66077 |
1979 | 1.63151 |
1978 | 1.62571 |
1977 | 1.60554 |
1976 | 1.58248 |
1975 | 1.58438 |
1974 | 1.58406 |
1973 | 1.5704 |
1972 | 1.55153 |
1971 | 1.5438 |
1970 | 1.54244 |
1969 | 1.54672 |
1968 | 1.56518 |
1967 | 1.58732 |
1966 | 1.58808 |
1965 | 1.57697 |
1964 | 1.57119 |
1963 | 1.56671 |
1962 | 1.56213 |
1961 | 1.55372 |
1960 | 1.53784 |