Bi-annual	US dollars
1987-06-30	2040
1987-12-31	2689
1988-06-30	2748
1988-12-31	3021
1989-06-30	5348
1989-12-31	3870
1990-06-30	4288
1990-12-31	5325
1991-06-30	4581
1991-12-31	6181
1992-06-30	6171
1992-12-31	6163
1993-06-30	5372
1993-12-31	6206
1994-06-30	6503
1994-12-31	6947
1995-06-30	6501
1995-12-31	5898
1996-06-30	5447
1996-12-31	5168
1997-06-30	8786
1997-12-31	8789
1998-06-30	8650
1998-12-31	9876
1999-06-30	10435