Bi-annual US dollars 1987-06-30 69 1987-12-31 202 1988-06-30 143 1988-12-31 221 1989-06-30 200 1989-12-31 248 1990-06-30 267 1990-12-31 328 1991-06-30 238 1991-12-31 118 1992-06-30 72 1992-12-31 144 1993-06-30 101 1993-12-31 157 1994-06-30 201 1994-12-31 205 1995-06-30 259 1995-12-31 349 1996-06-30 238 1996-12-31 274 1997-06-30 318 1997-12-31 219 1998-06-30 272 1998-12-31 275 1999-06-30 192