Bi-annual	US dollars
1987-06-30	3391
1987-12-31	3727
1988-06-30	2596
1988-12-31	2390
1989-06-30	2380
1989-12-31	2149
1990-06-30	2386
1990-12-31	2070
1991-06-30	2084
1991-12-31	2277
1992-06-30	2567
1992-12-31	2532
1993-06-30	3054
1993-12-31	2557
1994-06-30	3160
1994-12-31	2868
1995-06-30	2494
1995-12-31	3729
1996-06-30	4911
1996-12-31	5424
1997-06-30	7212
1997-12-31	6550
1998-06-30	6177
1998-12-31	8455
1999-06-30	8348