Bi-annual US dollars 1987-06-30 453 1987-12-31 630 1988-06-30 756 1988-12-31 541 1989-06-30 440 1989-12-31 506 1990-06-30 945 1990-12-31 621 1991-06-30 616 1991-12-31 607 1992-06-30 624 1992-12-31 635 1993-06-30 1101 1993-12-31 1140 1994-06-30 1728 1994-12-31 1973 1995-06-30 1718 1995-12-31 1871 1996-06-30 1891 1996-12-31 1991 1997-06-30 1946 1997-12-31 2188 1998-06-30 2706 1998-12-31 2671 1999-06-30 2548