Bi-annual US dollars 1987-06-30 1092 1987-12-31 1034 1988-06-30 752 1988-12-31 495 1989-06-30 736 1989-12-31 497 1990-06-30 664 1990-12-31 571 1991-06-30 506 1991-12-31 586 1992-06-30 710 1992-12-31 529 1993-06-30 1232 1993-12-31 1230 1994-06-30 1323 1994-12-31 1608 1995-06-30 1373 1995-12-31 1777 1996-06-30 1274 1996-12-31 1676 1997-06-30 2745 1997-12-31 2076 1998-06-30 1892 1998-12-31 2288 1999-06-30 2116