Bi-annual US dollars 1987-06-30 89 1987-12-31 94 1988-06-30 63 1988-12-31 47 1989-06-30 33 1989-12-31 53 1990-06-30 58 1990-12-31 68 1991-06-30 60 1991-12-31 45 1992-06-30 49 1992-12-31 61 1993-06-30 78 1993-12-31 61 1994-06-30 65 1994-12-31 77 1995-06-30 60 1995-12-31 81 1996-06-30 40 1996-12-31 31 1997-06-30 70 1997-12-31 51 1998-06-30 75 1998-12-31 97 1999-06-30 58