Bi-annual US dollars 1987-06-30 755 1987-12-31 742 1988-06-30 539 1988-12-31 490 1989-06-30 524 1989-12-31 650 1990-06-30 610 1990-12-31 772 1991-06-30 504 1991-12-31 799 1992-06-30 521 1992-12-31 653 1993-06-30 2030 1993-12-31 2430 1994-06-30 1900 1994-12-31 1363 1995-06-30 1406 1995-12-31 1625 1996-06-30 1624 1996-12-31 1745 1997-06-30 2098 1997-12-31 1331 1998-06-30 2089 1998-12-31 2095 1999-06-30 1779