Bi-annual US dollars 1987-06-30 1037 1987-12-31 1357 1988-06-30 1265 1988-12-31 1253 1989-06-30 1327 1989-12-31 1521 1990-06-30 1498 1990-12-31 1324 1991-06-30 1091 1991-12-31 2512 1992-06-30 2440 1992-12-31 842 1993-06-30 738 1993-12-31 931 1994-06-30 1034 1994-12-31 1640 1995-06-30 2117 1995-12-31 1609 1996-06-30 1694 1996-12-31 1558 1997-06-30 1522 1997-12-31 1331 1998-06-30 2736 1998-12-31 1696 1999-06-30 1708