Bi-annual US dollars 1987-06-30 302 1987-12-31 408 1988-06-30 447 1988-12-31 344 1989-06-30 526 1989-12-31 479 1990-06-30 1046 1990-12-31 949 1991-06-30 688 1991-12-31 607 1992-06-30 769 1992-12-31 957 1993-06-30 999 1993-12-31 1039 1994-06-30 2137 1994-12-31 3373 1995-06-30 3907 1995-12-31 4541 1996-06-30 4571 1996-12-31 611 1997-06-30 1293 1997-12-31 2071 1998-06-30 1799 1998-12-31 1401 1999-06-30 1290