Bi-annual US dollars 1987-06-30 15 1987-12-31 49 1988-06-30 15 1988-12-31 81 1989-06-30 104 1989-12-31 106 1990-06-30 148 1990-12-31 193 1991-06-30 115 1991-12-31 75 1992-06-30 126 1992-12-31 100 1993-06-30 99 1993-12-31 44 1994-06-30 106 1994-12-31 233 1995-06-30 202 1995-12-31 197 1996-06-30 270 1996-12-31 402 1997-06-30 639 1997-12-31 1611 1998-06-30 2129 1998-12-31 3143 1999-06-30 3877