Bi-annual US dollars 1987-06-30 443 1987-12-31 672 1988-06-30 599 1988-12-31 548 1989-06-30 468 1989-12-31 892 1990-06-30 752 1990-12-31 710 1991-06-30 665 1991-12-31 895 1992-06-30 628 1992-12-31 648 1993-06-30 336 1993-12-31 248 1994-06-30 336 1994-12-31 291 1995-06-30 444 1995-12-31 515 1996-06-30 548 1996-12-31 524 1997-06-30 556 1997-12-31 2282 1998-06-30 2546 1998-12-31 2970 1999-06-30 2884