Year	2007 US$
1980	1.461
1981	2.28
1982	1.616
1983	5.411
1984	3.807
1985	4.538
1986	7.229
1987	11.38
1988	22.04
1989	28.68
1990	29.73
1991	39.54
1992	47.27
1993	42.07
1994	52.13
1995	38.62
1996	32.73
1997	41.04
1998	41.95
1999	44.27
2000	48.43
2001	47.32
2002	51.98
2003	41.65
2004	119.3
2005	42.53
2006	43.04
2007	45.51