Bi-annual	US dollars
1987-06-30	10438
1987-12-31	10682
1988-06-30	9037
1988-12-31	8203
1989-06-30	8184
1989-12-31	7629
1990-06-30	7975
1990-12-31	7604
1991-06-30	7337
1991-12-31	7947
1992-06-30	8714
1992-12-31	8419
1993-06-30	10382
1993-12-31	9937
1994-06-30	10143
1994-12-31	10870
1995-06-30	10213
1995-12-31	11712
1996-06-30	13160
1996-12-31	14617
1997-06-30	18406
1997-12-31	23992
1998-06-30	23516
1998-12-31	27316
1999-06-30	25598