Bi-annual	US dollars
1987-06-30	4747
1987-12-31	4491
1988-06-30	3783
1988-12-31	3359
1989-06-30	2724
1989-12-31	4020
1990-06-30	3444
1990-12-31	2694
1991-06-30	2987
1991-12-31	3506
1992-06-30	3490
1992-12-31	3492
1993-06-30	3334
1993-12-31	3076
1994-06-30	2559
1994-12-31	2663
1995-06-30	2886
1995-12-31	3396
1996-06-30	3487
1996-12-31	3508
1997-06-30	3763
1997-12-31	5754
1998-06-30	7576
1998-12-31	9095
1999-06-30	7526