Bi-annual US dollars 1987-06-30 1616 1987-12-31 1953 1988-06-30 2748 1988-12-31 2631 1989-06-30 3260 1989-12-31 4025 1990-06-30 4498 1990-12-31 6012 1991-06-30 5310 1991-12-31 6879 1992-06-30 7014 1992-12-31 6301 1993-06-30 6415 1993-12-31 4644 1994-06-30 4241 1994-12-31 4109 1995-06-30 4801 1995-12-31 4275 1996-06-30 5663 1996-12-31 4831 1997-06-30 4473 1997-12-31 5648 1998-06-30 6376 1998-12-31 7400 1999-06-30 6799