Bi-annual	US dollars
1987-06-30	1246
1987-12-31	1538
1988-06-30	1431
1988-12-31	1275
1989-06-30	1363
1989-12-31	1342
1990-06-30	1324
1990-12-31	1488
1991-06-30	1349
1991-12-31	1418
1992-06-30	1836
1992-12-31	1542
1993-06-30	1840
1993-12-31	2264
1994-06-30	2599
1994-12-31	2561
1995-06-30	2773
1995-12-31	2574
1996-06-30	2710
1996-12-31	2916
1997-06-30	3635
1997-12-31	3904
1998-06-30	4413
1998-12-31	3834
1999-06-30	5754