Bi-annual US dollars 1987-06-30 1113 1987-12-31 351 1988-06-30 426 1988-12-31 354 1989-06-30 403 1989-12-31 440 1990-06-30 671 1990-12-31 698 1991-06-30 590 1991-12-31 1132 1992-06-30 839 1992-12-31 811 1993-06-30 1155 1993-12-31 1994 1994-06-30 1159 1994-12-31 831 1995-06-30 766 1995-12-31 1222 1996-06-30 1219 1996-12-31 1500 1997-06-30 1838 1997-12-31 2475 1998-06-30 2099 1998-12-31 2060 1999-06-30 2277