Bi-annual US dollars 1987-06-30 2646 1987-12-31 3032 1988-06-30 2686 1988-12-31 3009 1989-06-30 2229 1989-12-31 2241 1990-06-30 1709 1990-12-31 1546 1991-06-30 1378 1991-12-31 1253 1992-06-30 1281 1992-12-31 1074 1993-06-30 1458 1993-12-31 1375 1994-06-30 1242 1994-12-31 835 1995-06-30 904 1995-12-31 723 1996-06-30 671 1996-12-31 786 1997-06-30 988 1997-12-31 907 1998-06-30 1027 1998-12-31 993 1999-06-30 1006