Bi-annual	US dollars
1987-06-30	33501
1987-12-31	33445
1988-06-30	31925
1988-12-31	31013
1989-06-30	30496
1989-12-31	26501
1990-06-30	22771
1990-12-31	20046
1991-06-30	19698
1991-12-31	19335
1992-06-30	20368
1992-12-31	19413
1993-06-30	22437
1993-12-31	24572
1994-06-30	23535
1994-12-31	25129
1995-06-30	26579
1995-12-31	28427
1996-06-30	29144
1996-12-31	33262
1997-06-30	38494
1997-12-31	43197
1998-06-30	44667
1998-12-31	44757
1999-06-30	40994