Bi-annual	US dollars
1987-06-30	3601
1987-12-31	3683
1988-06-30	3599
1988-12-31	3719
1989-06-30	3790
1989-12-31	3788
1990-06-30	3701
1990-12-31	2684
1991-06-30	2168
1991-12-31	2564
1992-06-30	2683
1992-12-31	2768
1993-06-30	2606
1993-12-31	2322
1994-06-30	2123
1994-12-31	1852
1995-06-30	1721
1995-12-31	1695
1996-06-30	1807
1996-12-31	1796
1997-06-30	2043
1997-12-31	2804
1998-06-30	3880
1998-12-31	2781
1999-06-30	2975