Quarter	Thousands
1987-03-31	70271
1987-06-30	96511
1987-09-30	108772
1987-12-31	80560
1988-03-31	73591
1988-06-30	110346
1988-09-30	111704
1988-12-31	87444
1989-03-31	53190
1989-06-30	52236
1989-09-30	100877
1989-12-31	96325
1990-03-31	97776
1990-06-30	84189
1990-09-30	80842
1990-12-31	78566
1991-03-31	69933
1991-06-30	91653
1991-09-30	83610
1991-12-31	70314
1992-03-31	73734
1992-06-30	90393
1992-09-30	91588
1992-12-31	70789
1993-03-31	104927
1993-06-30	115320
1993-09-30	107255
1993-12-31	84332
1994-03-31	78264
1994-06-30	98153
1994-09-30	97059
1994-12-31	86298
1995-03-31	77952
1995-06-30	83174
1995-09-30	98386
1995-12-31	86873
1996-03-31	80673
1996-06-30	111720
1996-09-30	118827
1996-12-31	119406
1997-03-31	111219
1997-06-30	180035
1997-09-30	206268
1997-12-31	155809
1998-03-31	148736
1998-06-30	195794
1998-09-30	181131
1998-12-31	153119
1999-03-31	156115
1999-06-30	216120
1999-09-30	207388
1999-12-31	178121
2000-03-31	178363
2000-06-30	219178
2000-09-30	176477
2000-12-31	170038
2001-03-31	194096
2001-06-30	292708
2001-09-30	269480
2001-12-31	213320
2002-03-31	250839
2002-06-30	314005
2002-09-30	269514
2002-12-31	231386
2003-03-31	189930
2003-06-30	254202
2003-09-30	273563
2003-12-31	247206
2004-03-31	238875
2004-06-30	278851
2004-09-30	209332
2004-12-31	155832
2005-03-31	155865
2005-06-30	222255
2005-09-30	222659
2005-12-31	204662
2006-03-31	204056
2006-06-30	247720
2006-09-30	227588
2006-12-31	211964
2007-03-31	187600
2007-06-30	237043
2007-09-30	197696
2007-12-31	135805
2008-03-31	119669
2008-06-30	112218
2008-09-30	74454
2008-12-31	61407
2009-03-31	81353
2009-06-30	125338
2009-09-30	138985
2009-12-31	123772