Bi-annual US dollars 1987-06-30 3 1987-12-31 9 1988-06-30 10 1988-12-31 5 1989-06-30 2 1989-12-31 6 1990-06-30 0 1990-12-31 0 1991-06-30 3 1991-12-31 11 1992-06-30 34 1992-12-31 68 1993-06-30 120 1993-12-31 191 1994-06-30 318 1994-12-31 347 1995-06-30 437 1995-12-31 357 1996-06-30 513 1996-12-31 856 1997-06-30 627 1997-12-31 1186 1998-06-30 1167 1998-12-31 1301 1999-06-30 1488