Bi-annual US dollars 1987-06-30 52 1987-12-31 42 1988-06-30 29 1988-12-31 58 1989-06-30 47 1989-12-31 18 1990-06-30 35 1990-12-31 44 1991-06-30 31 1991-12-31 45 1992-06-30 32 1992-12-31 79 1993-06-30 83 1993-12-31 49 1994-06-30 76 1994-12-31 97 1995-06-30 29 1995-12-31 31 1996-06-30 40 1996-12-31 39 1997-06-30 15 1997-12-31 8 1998-06-30 10 1998-12-31 3 1999-06-30 2