Bi-annual	US dollars
1987-06-30	21398
1987-12-31	22895
1988-06-30	23121
1988-12-31	20732
1989-06-30	21007
1989-12-31	21854
1990-06-30	22332
1990-12-31	22043
1991-06-30	18411
1991-12-31	19987
1992-06-30	19199
1992-12-31	18909
1993-06-30	41498
1993-12-31	42018
1994-06-30	45475
1994-12-31	44984
1995-06-30	49709
1995-12-31	55886
1996-06-30	58037
1996-12-31	61947
1997-06-30	68304
1997-12-31	76044
1998-06-30	73425
1998-12-31	67096
1999-06-30	63916