Bi-annual US dollars 1987-06-30 16 1987-12-31 45 1988-06-30 58 1988-12-31 43 1989-06-30 74 1989-12-31 84 1990-06-30 75 1990-12-31 71 1991-06-30 68 1991-12-31 69 1992-06-30 72 1992-12-31 112 1993-06-30 116 1993-12-31 192 1994-06-30 199 1994-12-31 191 1995-06-30 212 1995-12-31 175 1996-06-30 236 1996-12-31 267 1997-06-30 284 1997-12-31 296 1998-06-30 408 1998-12-31 383 1999-06-30 481