Bi-annual	US dollars
1987-06-30	10792
1987-12-31	10435
1988-06-30	9251
1988-12-31	8872
1989-06-30	7443
1989-12-31	9975
1990-06-30	9217
1990-12-31	8540
1991-06-30	7754
1991-12-31	8728
1992-06-30	8961
1992-12-31	8508
1993-06-30	10897
1993-12-31	11780
1994-06-30	11821
1994-12-31	13337
1995-06-30	13900
1995-12-31	15513
1996-06-30	17196
1996-12-31	19065
1997-06-30	21989
1997-12-31	25736
1998-06-30	27322
1998-12-31	29281
1999-06-30	25793