Bi-annual US dollars 1987-06-30 21 1987-12-31 21 1988-06-30 9 1988-12-31 9 1989-06-30 22 1989-12-31 21 1990-06-30 24 1990-12-31 29 1991-06-30 75 1991-12-31 157 1992-06-30 110 1992-12-31 135 1993-06-30 173 1993-12-31 139 1994-06-30 165 1994-12-31 213 1995-06-30 100 1995-12-31 143 1996-06-30 146 1996-12-31 164 1997-06-30 627 1997-12-31 819 1998-06-30 1631 1998-12-31 1591 1999-06-30 1030