Bi-annual	US dollars
1987-06-30	1712
1987-12-31	1989
1988-06-30	1936
1988-12-31	1752
1989-06-30	1818
1989-12-31	2022
1990-06-30	1781
1990-12-31	1928
1991-06-30	1774
1991-12-31	1773
1992-06-30	2084
1992-12-31	1898
1993-06-30	2363
1993-12-31	2844
1994-06-30	3319
1994-12-31	3118
1995-06-30	3470
1995-12-31	2702
1996-06-30	3232
1996-12-31	3477
1997-06-30	4740
1997-12-31	4712
1998-06-30	4969
1998-12-31	5975
1999-06-30	7338