年份 | 美国 |
---|---|
2023 | - |
2022 | 7.04072 |
2021 | 4.49279 |
2020 | 1.30491 |
2019 | 1.79393 |
2018 | 2.40406 |
2017 | 1.89961 |
2016 | 1.00224 |
2015 | 1.00054 |
2014 | 1.86989 |
2013 | 1.75095 |
2012 | 1.8706 |
2011 | 2.07771 |
2010 | 1.20179 |
2009 | 0.640955 |
2008 | 1.91793 |
2007 | 2.70253 |
2006 | 3.08558 |
2005 | 3.13582 |
2004 | 2.68441 |
2003 | 1.9736 |
2002 | 1.55853 |
2001 | 2.25295 |
2000 | 2.26555 |
1999 | 1.40923 |
1998 | 1.12553 |
1997 | 1.72443 |
1996 | 1.83097 |
1995 | 2.0969 |
1994 | 2.13542 |
1993 | 2.37034 |
1992 | 2.27891 |
1991 | 3.38176 |
1990 | 3.74333 |
1989 | 3.92035 |
1988 | 3.52742 |
1987 | 2.47281 |
1986 | 2.0139 |
1985 | 3.16245 |
1984 | 3.60771 |
1983 | 3.91679 |
1982 | 6.17827 |
1981 | 9.46214 |
1980 | 9.03308 |
1979 | 8.29656 |
1978 | 7.03383 |
1977 | 6.21337 |
1976 | 5.50339 |
1975 | 9.26261 |
1974 | 8.99869 |
1973 | 5.47988 |
1972 | 4.32275 |
1971 | 5.06917 |
1970 | 5.53528 |
1969 | 4.95849 |
1968 | 4.36719 |
1967 | 3.15128 |
1966 | 2.89878 |
1965 | 1.91983 |
1964 | 1.50394 |
1963 | 1.08839 |
1962 | 1.24463 |
1961 | 1.35015 |
1960 | - |