Year	constant 2015 US$
1991	249650000
1992	334240000
1993	250230000
1994	150310000
1995	245060000
1996	97320000
1997	76070000
1998	54050000
1999	55120000
2000	51680000
2001	59150000
2002	56160000
2003	56630000
2004	55860000