Bi-annual US dollars 1987-06-30 76 1987-12-31 23 1988-06-30 73 1988-12-31 25 1989-06-30 31 1989-12-31 68 1990-06-30 89 1990-12-31 44 1991-06-30 42 1991-12-31 101 1992-06-30 65 1992-12-31 47 1993-06-30 137 1993-12-31 183 1994-06-30 221 1994-12-31 128 1995-06-30 86 1995-12-31 107 1996-06-30 461 1996-12-31 452 1997-06-30 70 1997-12-31 79 1998-06-30 42 1998-12-31 87 1999-06-30 43