Bi-annual US dollars 1987-06-30 45 1987-12-31 32 1988-06-30 46 1988-12-31 36 1989-06-30 22 1989-12-31 55 1990-06-30 61 1990-12-31 29 1991-06-30 41 1991-12-31 37 1992-06-30 48 1992-12-31 14 1993-06-30 21 1993-12-31 28 1994-06-30 29 1994-12-31 59 1995-06-30 54 1995-12-31 96 1996-06-30 48 1996-12-31 68 1997-06-30 161 1997-12-31 217 1998-06-30 230 1998-12-31 238 1999-06-30 30