Bi-annual US dollars 1987-06-30 27 1987-12-31 47 1988-06-30 43 1988-12-31 43 1989-06-30 62 1989-12-31 105 1990-06-30 138 1990-12-31 44 1991-06-30 52 1991-12-31 15 1992-06-30 38 1992-12-31 132 1993-06-30 62 1993-12-31 58 1994-06-30 26 1994-12-31 50 1995-06-30 105 1995-12-31 71 1996-06-30 64 1996-12-31 31 1997-06-30 47 1997-12-31 79 1998-06-30 100 1998-12-31 58 1999-06-30 80