Bi-annual	US dollars
1987-06-30	4688
1987-12-31	5469
1988-06-30	5074
1988-12-31	4601
1989-06-30	4869
1989-12-31	5060
1990-06-30	6039
1990-12-31	7064
1991-06-30	6522
1991-12-31	6562
1992-06-30	6900
1992-12-31	7926
1993-06-30	10359
1993-12-31	11593
1994-06-30	13702
1994-12-31	16299
1995-06-30	18021
1995-12-31	18079
1996-06-30	20818
1996-12-31	19686
1997-06-30	28131
1997-12-31	38138
1998-06-30	44680
1998-12-31	59197
1999-06-30	64917