Bi-annual	US dollars
1987-06-30	937
1987-12-31	855
1988-06-30	889
1988-12-31	1000
1989-06-30	853
1989-12-31	619
1990-06-30	483
1990-12-31	538
1991-06-30	486
1991-12-31	461
1992-06-30	434
1992-12-31	448
1993-06-30	336
1993-12-31	260
1994-06-30	276
1994-12-31	291
1995-06-30	301
1995-12-31	316
1996-06-30	289
1996-12-31	272
1997-06-30	266
1997-12-31	229
1998-06-30	378
1998-12-31	403
1999-06-30	520