Bi-annual US dollars 1987-06-30 13 1987-12-31 23 1988-06-30 24 1988-12-31 5 1989-06-30 42 1989-12-31 29 1990-06-30 31 1990-12-31 8 1991-06-30 8 1991-12-31 21 1992-06-30 103 1992-12-31 89 1993-06-30 95 1993-12-31 80 1994-06-30 137 1994-12-31 166 1995-06-30 164 1995-12-31 119 1996-06-30 140 1996-12-31 103 1997-06-30 126 1997-12-31 156 1998-06-30 93 1998-12-31 37 1999-06-30 66