Bi-annual	US dollars
1987-06-30	3509
1987-12-31	4533
1988-06-30	4344
1988-12-31	5344
1989-06-30	4792
1989-12-31	4642
1990-06-30	4986
1990-12-31	6228
1991-06-30	4796
1991-12-31	5204
1992-06-30	5726
1992-12-31	5169
1993-06-30	7312
1993-12-31	7335
1994-06-30	8043
1994-12-31	7464
1995-06-30	6492
1995-12-31	5786
1996-06-30	4928
1996-12-31	5085
1997-06-30	7185
1997-12-31	10132
1998-06-30	10682
1998-12-31	11656
1999-06-30	11725