Bi-annual US dollars 1987-06-30 135 1987-12-31 87 1988-06-30 87 1988-12-31 235 1989-06-30 257 1989-12-31 292 1990-06-30 223 1990-12-31 330 1991-06-30 211 1991-12-31 314 1992-06-30 411 1992-12-31 1642 1993-06-30 3358 1993-12-31 4789 1994-06-30 2795 1994-12-31 4457 1995-06-30 4442 1995-12-31 4172 1996-06-30 3755 1996-12-31 4179 1997-06-30 6197 1997-12-31 5905 1998-06-30 5475 1998-12-31 4110 1999-06-30 3239