Bi-annual US dollars 1987-06-30 82 1987-12-31 100 1988-06-30 97 1988-12-31 67 1989-06-30 79 1989-12-31 124 1990-06-30 155 1990-12-31 100 1991-06-30 86 1991-12-31 149 1992-06-30 99 1992-12-31 61 1993-06-30 117 1993-12-31 152 1994-06-30 377 1994-12-31 171 1995-06-30 180 1995-12-31 191 1996-06-30 96 1996-12-31 111 1997-06-30 50 1997-12-31 92 1998-06-30 85 1998-12-31 75 1999-06-30 22