Bi-annual	US dollars
1987-06-30	4746
1987-12-31	5667
1988-06-30	5918
1988-12-31	5652
1989-06-30	4970
1989-12-31	5041
1990-06-30	8767
1990-12-31	9447
1991-06-30	7302
1991-12-31	8790
1992-06-30	11144
1992-12-31	10419
1993-06-30	12687
1993-12-31	10642
1994-06-30	12889
1994-12-31	8000
1995-06-30	10774
1995-12-31	11895
1996-06-30	12865
1996-12-31	12243
1997-06-30	15217
1997-12-31	19285
1998-06-30	22710
1998-12-31	25849
1999-06-30	27085