Bi-annual US dollars 1987-06-30 3049 1987-12-31 4778 1988-06-30 3851 1988-12-31 3124 1989-06-30 3396 1989-12-31 2770 1990-06-30 3017 1990-12-31 3159 1991-06-30 2552 1991-12-31 2393 1992-06-30 2221 1992-12-31 2419 1993-06-30 3543 1993-12-31 3800 1994-06-30 3728 1994-12-31 3337 1995-06-30 3105 1995-12-31 2392 1996-06-30 3665 1996-12-31 2907 1997-06-30 5250 1997-12-31 3062 1998-06-30 3136 1998-12-31 1617 1999-06-30 664