Bi-annual US dollars 1987-06-30 474 1987-12-31 466 1988-06-30 268 1988-12-31 566 1989-06-30 389 1989-12-31 360 1990-06-30 483 1990-12-31 617 1991-06-30 407 1991-12-31 544 1992-06-30 480 1992-12-31 424 1993-06-30 393 1993-12-31 445 1994-06-30 560 1994-12-31 318 1995-06-30 318 1995-12-31 375 1996-06-30 471 1996-12-31 282 1997-06-30 524 1997-12-31 711 1998-06-30 492 1998-12-31 371 1999-06-30 576