Bi-annual	US dollars
1987-06-30	1564
1987-12-31	1840
1988-06-30	2035
1988-12-31	2264
1989-06-30	2649
1989-12-31	2925
1990-06-30	3214
1990-12-31	3483
1991-06-30	3475
1991-12-31	4331
1992-06-30	3878
1992-12-31	3244
1993-06-30	4790
1993-12-31	5200
1994-06-30	6048
1994-12-31	5815
1995-06-30	5674
1995-12-31	5120
1996-06-30	4507
1996-12-31	4860
1997-06-30	4808
1997-12-31	4342
1998-06-30	2142
1998-12-31	2275
1999-06-30	3366