Bi-annual US dollars 1987-06-30 959 1987-12-31 932 1988-06-30 1010 1988-12-31 882 1989-06-30 901 1989-12-31 1071 1990-06-30 703 1990-12-31 762 1991-06-30 616 1991-12-31 749 1992-06-30 807 1992-12-31 783 1993-06-30 966 1993-12-31 1122 1994-06-30 1242 1994-12-31 1453 1995-06-30 1583 1995-12-31 1601 1996-06-30 1105 1996-12-31 1125 1997-06-30 795 1997-12-31 737 1998-06-30 1252 1998-12-31 1689 1999-06-30 1186