Bi-annual US dollars 1987-06-30 2 1987-12-31 0 1988-06-30 9 1988-12-31 170 1989-06-30 79 1989-12-31 252 1990-06-30 115 1990-12-31 62 1991-06-30 58 1991-12-31 105 1992-06-30 131 1992-12-31 68 1993-06-30 62 1993-12-31 21 1994-06-30 9 1994-12-31 33 1995-06-30 49 1995-12-31 48 1996-06-30 34 1996-12-31 31 1997-06-30 47 1997-12-31 35 1998-06-30 20 1998-12-31 10 1999-06-30 8