Bi-annual	US dollars
1987-06-30	21827
1987-12-31	22323
1988-06-30	21493
1988-12-31	21374
1989-06-30	20669
1989-12-31	18144
1990-06-30	15652
1990-12-31	15035
1991-06-30	14319
1991-12-31	14965
1992-06-30	14876
1992-12-31	14058
1993-06-30	14768
1993-12-31	14582
1994-06-30	14639
1994-12-31	15127
1995-06-30	15373
1995-12-31	15713
1996-06-30	14759
1996-12-31	15970
1997-06-30	16949
1997-12-31	20101
1998-06-30	22905
1998-12-31	23787
1999-06-30	21079