Bi-annual US dollars 1987-06-30 102 1987-12-31 75 1988-06-30 121 1988-12-31 63 1989-06-30 121 1989-12-31 118 1990-06-30 61 1990-12-31 79 1991-06-30 128 1991-12-31 93 1992-06-30 61 1992-12-31 58 1993-06-30 54 1993-12-31 68 1994-06-30 68 1994-12-31 58 1995-06-30 81 1995-12-31 119 1996-06-30 67 1996-12-31 108 1997-06-30 165 1997-12-31 174 1998-06-30 315 1998-12-31 434 1999-06-30 418