Bi-annual	US dollars
1987-06-30	1063
1987-12-31	843
1988-06-30	783
1988-12-31	931
1989-06-30	725
1989-12-31	700
1990-06-30	809
1990-12-31	571
1991-06-30	689
1991-12-31	463
1992-06-30	677
1992-12-31	582
1993-06-30	624
1993-12-31	804
1994-06-30	994
1994-12-31	621
1995-06-30	668
1995-12-31	603
1996-06-30	634
1996-12-31	491
1997-06-30	754
1997-12-31	586
1998-06-30	579
1998-12-31	506
1999-06-30	492