Bi-annual	US dollars
1987-06-30	1222
1987-12-31	1428
1988-06-30	1179
1988-12-31	1240
1989-06-30	1352
1989-12-31	1696
1990-06-30	2053
1990-12-31	2342
1991-06-30	2382
1991-12-31	2337
1992-06-30	2110
1992-12-31	2406
1993-06-30	2692
1993-12-31	3135
1994-06-30	4708
1994-12-31	5437
1995-06-30	4788
1995-12-31	3034
1996-06-30	5216
1996-12-31	5203
1997-06-30	7017
1997-12-31	8593
1998-06-30	9927
1998-12-31	9734
1999-06-30	14070