Bi-annual	US dollars
1987-06-30	8651
1987-12-31	8146
1988-06-30	7470
1988-12-31	6964
1989-06-30	7596
1989-12-31	6774
1990-06-30	6997
1990-12-31	7722
1991-06-30	7433
1991-12-31	8611
1992-06-30	9587
1992-12-31	9481
1993-06-30	14886
1993-12-31	15767
1994-06-30	16267
1994-12-31	17735
1995-06-30	19393
1995-12-31	22478
1996-06-30	25137
1996-12-31	28676
1997-06-30	33696
1997-12-31	35739
1998-06-30	32527
1998-12-31	30826
1999-06-30	28078