年份 | 美国 |
---|---|
2023 | - |
2022 | 6.4352 |
2021 | 6.43917 |
2020 | 6.41389 |
2019 | 6.37965 |
2018 | 6.32756 |
2017 | 6.23906 |
2016 | 6.22281 |
2015 | 6.14027 |
2014 | 5.89149 |
2013 | 5.71627 |
2012 | 5.68564 |
2011 | 5.58381 |
2010 | 5.40603 |
2009 | 5.30186 |
2008 | 5.16723 |
2007 | 4.94083 |
2006 | 4.6613 |
2005 | 4.48082 |
2004 | 4.38508 |
2003 | 4.25332 |
2002 | 4.1152 |
2001 | 4.04212 |
2000 | 3.99298 |
1999 | 3.93668 |
1998 | 3.89364 |
1997 | 3.87183 |
1996 | 3.87986 |
1995 | 3.90829 |
1994 | 3.99508 |
1993 | 4.09384 |
1992 | 4.19044 |
1991 | 4.32269 |
1990 | 4.42196 |
1989 | 4.44315 |
1988 | 4.56153 |
1987 | 4.70131 |
1986 | 4.69572 |
1985 | 4.73105 |
1984 | 4.83619 |
1983 | 4.77672 |
1982 | 4.6591 |
1981 | 4.66143 |
1980 | 4.62047 |
1979 | 4.50665 |
1978 | 4.46457 |
1977 | 4.52901 |
1976 | 4.59356 |
1975 | 4.63697 |
1974 | 4.66167 |
1973 | 4.66078 |
1972 | 4.62343 |
1971 | 4.51815 |
1970 | 4.42244 |
1969 | 4.35443 |
1968 | 4.23706 |
1967 | 4.15303 |
1966 | 4.11451 |
1965 | 4.04071 |
1964 | 4.00105 |
1963 | 4.06795 |
1962 | 4.11681 |
1961 | 4.13437 |
1960 | 4.20667 |