| 年份 | 美国 |
|---|---|
| 2023 | - |
| 2022 | - |
| 2021 | 8268 |
| 2020 | 8145.3 |
| 2019 | 8006.1 |
| 2018 | 8196.4 |
| 2017 | 8281.3 |
| 2016 | 8614.2 |
| 2015 | 7430.1 |
| 2014 | 7638.1 |
| 2013 | 7300.9 |
| 2012 | 5911.9 |
| 2011 | 6803.5 |
| 2010 | 6978.1 |
| 2009 | 7226.2 |
| 2008 | 6598.3 |
| 2007 | 6704.4 |
| 2006 | 6400.4 |
| 2005 | 6450.7 |
| 2004 | 6851.1 |
| 2003 | 6023.7 |
| 2002 | 5546.8 |
| 2001 | 5891.1 |
| 2000 | 5854.3 |
| 1999 | 5736.5 |
| 1998 | 5676.5 |
| 1997 | 5275.3 |
| 1996 | 5175.3 |
| 1995 | 4644.8 |
| 1994 | 5560 |
| 1993 | 4298.8 |
| 1992 | 5357.8 |
| 1991 | 4507.6 |
| 1990 | 4755.1 |
| 1989 | 4473.9 |
| 1988 | 3706.9 |
| 1987 | 4735.4 |
| 1986 | 4698.9 |
| 1985 | 4763.3 |
| 1984 | 4374.1 |
| 1983 | 3535.9 |
| 1982 | 4370.6 |
| 1981 | 4256.7 |
| 1980 | 3771.9 |
| 1979 | 4426.2 |
| 1978 | 4109.8 |
| 1977 | 3683.2 |
| 1976 | 3533 |
| 1975 | 3461.3 |
| 1974 | 2997.5 |
| 1973 | 3683.2 |
| 1972 | 3908.2 |
| 1971 | 3725.6 |
| 1970 | 3154.9 |
| 1969 | 3464.3 |
| 1968 | 3212.8 |
| 1967 | 3161.2 |
| 1966 | 3016.7 |
| 1965 | 3040.8 |
| 1964 | 2639.3 |
| 1963 | 2800.6 |
| 1962 | 2683.1 |
| 1961 | 2522.3 |
| 1960 | - |