Bi-annual US dollars 1987-06-30 8 1987-12-31 19 1988-06-30 15 1988-12-31 33 1989-06-30 48 1989-12-31 47 1990-06-30 54 1990-12-31 29 1991-06-30 29 1991-12-31 35 1992-06-30 27 1992-12-31 36 1993-06-30 54 1993-12-31 78 1994-06-30 23 1994-12-31 28 1995-06-30 51 1995-12-31 40 1996-06-30 62 1996-12-31 86 1997-06-30 42 1997-12-31 84 1998-06-30 45 1998-12-31 2 1999-06-30 2