| 1937 - 50 1951 - 54 1955 - 58 1959 - 65 1966 - 67 1968 - 71 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 | $ 3,000 3,600 4,200 4,800 6,600 7,800 9,000 10,800 13,200 14,100 15,300 16,500 17,700 22,900 25,900 29,700 32,400 35,700 37,800 39,600 | | 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 | $42,000 43,800 45,000 48,000 51,300 53,400 55,500 57,600 60,600 61,200 62,700 65,400 68,400 72,600 76,200 80,400 84,900 87,000 87,900 90,000 94,200 97,500 |