Bi-annual	US dollars
1987-06-30	8435
1987-12-31	7933
1988-06-30	8921
1988-12-31	7368
1989-06-30	7877
1989-12-31	8129
1990-06-30	7260
1990-12-31	7562
1991-06-30	6452
1991-12-31	6696
1992-06-30	6449
1992-12-31	5934
1993-06-30	16298
1993-12-31	16438
1994-06-30	17887
1994-12-31	18456
1995-06-30	19409
1995-12-31	21330
1996-06-30	24284
1996-12-31	26139
1997-06-30	29752
1997-12-31	33959
1998-06-30	32886
1998-12-31	28180
1999-06-30	25812