Year	US Dollars adjusted for inflation)
1970	13550
1971	13970
1972	14510
1973	15090
1974	15000
1975	14890
1976	15630
1977	16110
1978	16630
1979	17370
1980	17550
1981	17470
1982	17300
1983	17660
1984	18090
1985	18400
1986	18880
1987	19130
1988	19740
1989	20340
1990	21280
1991	22130
1992	22480
1993	22160
1994	22630
1995	22950
1996	23070
1997	23420
1998	23870
1999	24320
2000	25060
2001	25320
2002	25260
2003	25190
2004	25610