Bi-annual	US dollars
1987-06-30	7622
1987-12-31	9441
1988-06-30	9135
1988-12-31	9675
1989-06-30	9768
1989-12-31	10102
1990-06-30	10797
1990-12-31	13400
1991-06-30	11159
1991-12-31	12643
1992-06-30	13704
1992-12-31	12626
1993-06-30	15371
1993-12-31	14170
1994-06-30	15014
1994-12-31	12429
1995-06-30	9998
1995-12-31	8403
1996-06-30	6522
1996-12-31	7336
1997-06-30	9992
1997-12-31	16474
1998-06-30	17685
1998-12-31	19101
1999-06-30	19368