Bi-annual US dollars 1987-06-30 1334 1987-12-31 1370 1988-06-30 1109 1988-12-31 976 1989-06-30 1152 1989-12-31 893 1990-06-30 724 1990-12-31 396 1991-06-30 345 1991-12-31 502 1992-06-30 508 1992-12-31 542 1993-06-30 605 1993-12-31 746 1994-06-30 1114 1994-12-31 1166 1995-06-30 1416 1995-12-31 1403 1996-06-30 1450 1996-12-31 2133 1997-06-30 2267 1997-12-31 1886 1998-06-30 1822 1998-12-31 1438 1999-06-30 1384