Bi-annual US dollars 1987-06-30 58 1987-12-31 57 1988-06-30 111 1988-12-31 859 1989-06-30 40 1989-12-31 85 1990-06-30 42 1990-12-31 114 1991-06-30 79 1991-12-31 62 1992-06-30 30 1992-12-31 80 1993-06-30 23 1993-12-31 67 1994-06-30 142 1994-12-31 120 1995-06-30 148 1995-12-31 186 1996-06-30 180 1996-12-31 308 1997-06-30 318 1997-12-31 411 1998-06-30 363 1998-12-31 359 1999-06-30 442