Bi-annual	US dollars
1987-06-30	8651
1987-12-31	7931
1988-06-30	7276
1988-12-31	7022
1989-06-30	6846
1989-12-31	6008
1990-06-30	5855
1990-12-31	6242
1991-06-30	6243
1991-12-31	7344
1992-06-30	7762
1992-12-31	7267
1993-06-30	11495
1993-12-31	13357
1994-06-30	14418
1994-12-31	15891
1995-06-30	17465
1995-12-31	20516
1996-06-30	22538
1996-12-31	25986
1997-06-30	29514
1997-12-31	32055
1998-06-30	30080
1998-12-31	28624
1999-06-30	25778