Bi-annual US dollars 1987-06-30 163 1987-12-31 257 1988-06-30 346 1988-12-31 313 1989-06-30 215 1989-12-31 574 1990-06-30 309 1990-12-31 430 1991-06-30 576 1991-12-31 678 1992-06-30 620 1992-12-31 400 1993-06-30 482 1993-12-31 545 1994-06-30 600 1994-12-31 501 1995-06-30 555 1995-12-31 512 1996-06-30 395 1996-12-31 544 1997-06-30 572 1997-12-31 515 1998-06-30 617 1998-12-31 619 1999-06-30 900