Bi-annual US dollars 1987-06-30 77 1987-12-31 119 1988-06-30 133 1988-12-31 145 1989-06-30 116 1989-12-31 110 1990-06-30 70 1990-12-31 58 1991-06-30 45 1991-12-31 65 1992-06-30 91 1992-12-31 88 1993-06-30 89 1993-12-31 90 1994-06-30 90 1994-12-31 59 1995-06-30 59 1995-12-31 36 1996-06-30 39 1996-12-31 39 1997-06-30 47 1997-12-31 44 1998-06-30 50 1998-12-31 58 1999-06-30 44