Bi-annual US dollars 1987-06-30 610 1987-12-31 504 1988-06-30 462 1988-12-31 414 1989-06-30 535 1989-12-31 361 1990-06-30 534 1990-12-31 369 1991-06-30 538 1991-12-31 611 1992-06-30 940 1992-12-31 665 1993-06-30 1663 1993-12-31 2499 1994-06-30 2194 1994-12-31 2613 1995-06-30 2870 1995-12-31 3278 1996-06-30 3002 1996-12-31 2614 1997-06-30 3029 1997-12-31 2787 1998-06-30 3288 1998-12-31 3125 1999-06-30 2189