Bi-annual	US dollars
1987-06-30	2227
1987-12-31	1868
1988-06-30	1649
1988-12-31	1683
1989-06-30	1532
1989-12-31	1355
1990-06-30	1475
1990-12-31	1113
1991-06-30	963
1991-12-31	1192
1992-06-30	1793
1992-12-31	1676
1993-06-30	2360
1993-12-31	2652
1994-06-30	2968
1994-12-31	2555
1995-06-30	2380
1995-12-31	2704
1996-06-30	2519
1996-12-31	2948
1997-06-30	2158
1997-12-31	2425
1998-06-30	3248
1998-12-31	2784
1999-06-30	3447