Bi-annual	US dollars
1987-06-30	10944
1987-12-31	13147
1988-06-30	13927
1988-12-31	10099
1989-06-30	13068
1989-12-31	11241
1990-06-30	13295
1990-12-31	11479
1991-06-30	9711
1991-12-31	10800
1992-06-30	14724
1992-12-31	14323
1993-06-30	15191
1993-12-31	16880
1994-06-30	18484
1994-12-31	21729
1995-06-30	24404
1995-12-31	20782
1996-06-30	22749
1996-12-31	20278
1997-06-30	22612
1997-12-31	27129
1998-06-30	29284
1998-12-31	21374
1999-06-30	31706