Bi-annual US dollars 1987-06-30 105 1987-12-31 109 1988-06-30 182 1988-12-31 52 1989-06-30 43 1989-12-31 40 1990-06-30 77 1990-12-31 266 1991-06-30 91 1991-12-31 49 1992-06-30 91 1992-12-31 88 1993-06-30 143 1993-12-31 112 1994-06-30 51 1994-12-31 131 1995-06-30 97 1995-12-31 70 1996-06-30 84 1996-12-31 108 1997-06-30 98 1997-12-31 92 1998-06-30 143 1998-12-31 47 1999-06-30 54