Bi-annual US dollars 1987-06-30 77 1987-12-31 87 1988-06-30 75 1988-12-31 72 1989-06-30 12 1989-12-31 15 1990-06-30 30 1990-12-31 29 1991-06-30 49 1991-12-31 17 1992-06-30 89 1992-12-31 48 1993-06-30 78 1993-12-31 112 1994-06-30 125 1994-12-31 113 1995-06-30 177 1995-12-31 171 1996-06-30 224 1996-12-31 176 1997-06-30 328 1997-12-31 174 1998-06-30 287 1998-12-31 359 1999-06-30 374