Bi-annual	US dollars
1987-06-30	535
1987-12-31	689
1988-06-30	645
1988-12-31	575
1989-06-30	530
1989-12-31	522
1990-06-30	520
1990-12-31	612
1991-06-30	634
1991-12-31	581
1992-06-30	596
1992-12-31	539
1993-06-30	876
1993-12-31	857
1994-06-30	974
1994-12-31	956
1995-06-30	1047
1995-12-31	961
1996-06-30	1027
1996-12-31	990
1997-06-30	995
1997-12-31	888
1998-06-30	959
1998-12-31	962
1999-06-30	943