Bi-annual US dollars 1987-06-30 13 1987-12-31 9 1988-06-30 29 1988-12-31 33 1989-06-30 22 1989-12-31 32 1990-06-30 134 1990-12-31 21 1991-06-30 71 1991-12-31 82 1992-06-30 34 1992-12-31 36 1993-06-30 29 1993-12-31 22 1994-06-30 117 1994-12-31 25 1995-06-30 27 1995-12-31 33 1996-06-30 28 1996-12-31 36 1997-06-30 30 1997-12-31 36 1998-06-30 80 1998-12-31 95 1999-06-30 106