Bi-annual US dollars 1987-06-30 37 1987-12-31 13 1988-06-30 41 1988-12-31 7 1989-06-30 76 1989-12-31 52 1990-06-30 98 1990-12-31 44 1991-06-30 73 1991-12-31 106 1992-06-30 169 1992-12-31 103 1993-06-30 77 1993-12-31 146 1994-06-30 51 1994-12-31 94 1995-06-30 70 1995-12-31 111 1996-06-30 25 1996-12-31 48 1997-06-30 48 1997-12-31 48 1998-06-30 138 1998-12-31 163 1999-06-30 43