Bi-annual US dollars 1987-06-30 16883 1987-12-31 17781 1988-06-30 17846 1988-12-31 15782 1989-06-30 15187 1989-12-31 16489 1990-06-30 16270 1990-12-31 16426 1991-06-30 13240 1991-12-31 14718 1992-06-30 13894 1992-12-31 13443 1993-06-30 28591 1993-12-31 27934 1994-06-30 30440 1994-12-31 28558 1995-06-30 31886 1995-12-31 36285 1996-06-30 36495 1996-12-31 39333 1997-06-30 41274 1997-12-31 40624 1998-06-30 40097 1998-12-31 36129 1999-06-30 33324