Bi-annual US dollars 1987-06-30 116 1987-12-31 123 1988-06-30 111 1988-12-31 107 1989-06-30 109 1989-12-31 106 1990-06-30 136 1990-12-31 183 1991-06-30 120 1991-12-31 185 1992-06-30 154 1992-12-31 368 1993-06-30 200 1993-12-31 352 1994-06-30 335 1994-12-31 604 1995-06-30 447 1995-12-31 521 1996-06-30 432 1996-12-31 380 1997-06-30 853 1997-12-31 763 1998-06-30 787 1998-12-31 727 1999-06-30 858