Bi-annual	US dollars
1987-06-30	5958
1987-12-31	5646
1988-06-30	4356
1988-12-31	4082
1989-06-30	4341
1989-12-31	4404
1990-06-30	4414
1990-12-31	4077
1991-06-30	3781
1991-12-31	4145
1992-06-30	4522
1992-12-31	4628
1993-06-30	5226
1993-12-31	5049
1994-06-30	4735
1994-12-31	4556
1995-06-30	4434
1995-12-31	5269
1996-06-30	6383
1996-12-31	7096
1997-06-30	7837
1997-12-31	10931
1998-06-30	10826
1998-12-31	13582
1999-06-30	12149