Year	US Dollars adjusted for inflation)
1980	14.21
1981	14.26
1982	14.67
1983	15.16
1984	15.6
1985	16.1
1986	16.72
1987	17.26
1988	17.84
1989	18.72
1990	19.16
1991	19.28
1992	19.9
1993	20.94
1994	21.75
1995	22.2
1996	22.73
1997	23.4
1998	24.27
1999	24.54
2000	25.43
2001	25.96
2002	26.23
2003	26.79
2004	27.61
2005	28.12
2006	29.29