Bi-annual	US dollars
1987-06-30	1542
1987-12-31	1713
1988-06-30	1550
1988-12-31	1625
1989-06-30	1603
1989-12-31	1572
1990-06-30	1472
1990-12-31	1457
1991-06-30	947
1991-12-31	997
1992-06-30	1033
1992-12-31	1007
1993-06-30	1461
1993-12-31	2502
1994-06-30	2140
1994-12-31	3060
1995-06-30	2593
1995-12-31	2664
1996-06-30	2787
1996-12-31	2695
1997-06-30	3144
1997-12-31	3472
1998-06-30	4053
1998-12-31	4837
1999-06-30	4240