Bi-annual US dollars 1987-06-30 52 1987-12-31 26 1988-06-30 36 1988-12-31 16 1989-06-30 47 1989-12-31 23 1990-06-30 58 1990-12-31 8 1991-06-30 28 1991-12-31 22 1992-06-30 48 1992-12-31 35 1993-06-30 54 1993-12-31 12 1994-06-30 20 1994-12-31 27 1995-06-30 24 1995-12-31 68 1996-06-30 113 1996-12-31 115 1997-06-30 47 1997-12-31 69 1998-06-30 137 1998-12-31 100 1999-06-30 244