Bi-annual	US dollars
1987-06-30	505
1987-12-31	481
1988-06-30	513
1988-12-31	530
1989-06-30	533
1989-12-31	577
1990-06-30	532
1990-12-31	538
1991-06-30	475
1991-12-31	495
1992-06-30	531
1992-12-31	535
1993-06-30	707
1993-12-31	712
1994-06-30	765
1994-12-31	918
1995-06-30	875
1995-12-31	861
1996-06-30	991
1996-12-31	1019
1997-06-30	1073
1997-12-31	1497
1998-06-30	1771
1998-12-31	2012
1999-06-30	1503