Bi-annual	US dollars
1987-06-30	10839
1987-12-31	10177
1988-06-30	9324
1988-12-31	8537
1989-06-30	8785
1989-12-31	7103
1990-06-30	6148
1990-12-31	5376
1991-06-30	5304
1991-12-31	6502
1992-06-30	7378
1992-12-31	7696
1993-06-30	10400
1993-12-31	11796
1994-06-30	12483
1994-12-31	14104
1995-06-30	14613
1995-12-31	16935
1996-06-30	16536
1996-12-31	20142
1997-06-30	22517
1997-12-31	24271
1998-06-30	23142
1998-12-31	21020
1999-06-30	18636