Bi-annual US dollars 1987-06-30 1317 1987-12-31 217 1988-06-30 285 1988-12-31 193 1989-06-30 212 1989-12-31 268 1990-06-30 187 1990-12-31 220 1991-06-30 139 1991-12-31 200 1992-06-30 67 1992-12-31 359 1993-06-30 24 1993-12-31 145 1994-06-30 443 1994-12-31 358 1995-06-30 310 1995-12-31 448 1996-06-30 1011 1996-12-31 878 1997-06-30 987 1997-12-31 405 1998-06-30 415 1998-12-31 516 1999-06-30 6