Bi-annual US dollars 1987-06-30 0 1987-12-31 0 1988-06-30 0 1988-12-31 0 1989-06-30 25 1989-12-31 0 1990-06-30 0 1990-12-31 585 1991-06-30 663 1991-12-31 960 1992-06-30 991 1992-12-31 912 1993-06-30 578 1993-12-31 474 1994-06-30 417 1994-12-31 322 1995-06-30 251 1995-12-31 250 1996-06-30 124 1996-12-31 98 1997-06-30 91 1997-12-31 102 1998-06-30 225 1998-12-31 138 1999-06-30 148