Bi-annual	US dollars
1987-06-30	1216
1987-12-31	1812
1988-06-30	834
1988-12-31	1148
1989-06-30	1107
1989-12-31	826
1990-06-30	1243
1990-12-31	988
1991-06-30	752
1991-12-31	771
1992-06-30	904
1992-12-31	1051
1993-06-30	879
1993-12-31	817
1994-06-30	1492
1994-12-31	998
1995-06-30	1282
1995-12-31	1859
1996-06-30	2334
1996-12-31	2815
1997-06-30	3806
1997-12-31	2860
1998-06-30	1607
1998-12-31	2015
1999-06-30	1148