Bi-annual	US dollars
1987-06-30	5236
1987-12-31	5731
1988-06-30	3740
1988-12-31	3847
1989-06-30	3544
1989-12-31	3146
1990-06-30	2773
1990-12-31	3321
1991-06-30	3613
1991-12-31	5273
1992-06-30	5521
1992-12-31	6748
1993-06-30	17683
1993-12-31	19858
1994-06-30	13159
1994-12-31	42816
1995-06-30	48864
1995-12-31	55333
1996-06-30	57184
1996-12-31	71377
1997-06-30	73789
1997-12-31	85097
1998-06-30	98264
1998-12-31	102403
1999-06-30	98881