Bi-annual US dollars 1987-06-30 1669 1987-12-31 634 1988-06-30 720 1988-12-31 635 1989-06-30 569 1989-12-31 766 1990-06-30 443 1990-12-31 450 1991-06-30 399 1991-12-31 512 1992-06-30 388 1992-12-31 670 1993-06-30 312 1993-12-31 795 1994-06-30 1247 1994-12-31 1212 1995-06-30 1152 1995-12-31 1222 1996-06-30 1877 1996-12-31 1827 1997-06-30 2058 1997-12-31 1790 1998-06-30 2096 1998-12-31 2310 1999-06-30 1965