Bi-annual	US dollars
1987-06-30	19776
1987-12-31	20778
1988-06-30	20072
1988-12-31	21723
1989-06-30	19094
1989-12-31	17275
1990-06-30	14547
1990-12-31	12893
1991-06-30	12816
1991-12-31	11457
1992-06-30	11049
1992-12-31	9835
1993-06-30	9870
1993-12-31	10107
1994-06-30	10018
1994-12-31	9357
1995-06-30	9376
1995-12-31	9425
1996-06-30	9680
1996-12-31	11184
1997-06-30	12429
1997-12-31	13475
1998-06-30	14719
1998-12-31	15092
1999-06-30	13598