Quarter	Number of Buildings
1999-01-01	951
1999-04-01	1188
1999-07-01	1074
1999-10-01	816
2000-01-01	786
2000-04-01	966
2000-07-01	936
2000-10-01	782
2001-01-01	830
2001-04-01	885
2001-07-01	864
2001-10-01	662
2002-01-01	847
2002-04-01	823
2002-07-01	777
2002-10-01	659
2003-01-01	845
2003-04-01	979
2003-07-01	892
2003-10-01	778
2004-01-01	801
2004-04-01	960
2004-07-01	978
2004-10-01	901
2005-01-01	846
2005-04-01	1141
2005-07-01	1142
2005-10-01	948
2006-01-01	986
2006-04-01	1276
2006-07-01	1193
2006-10-01	1094
2007-01-01	1014
2007-04-01	1200
2007-07-01	1247
2007-10-01	991
2008-01-01	1003
2008-04-01	1166
2008-07-01	1017
2008-10-01	903
2009-01-01	905
2009-04-01	956
2009-07-01	846
2009-10-01	754
2010-01-01	658
2010-04-01	741
2010-07-01	773
2010-10-01	629
2011-01-01	711
2011-04-01	745
2011-07-01	620
2011-10-01	509
2012-01-01	493
2012-04-01	560
2012-07-01	605
2012-10-01	683
2013-01-01	613
2013-04-01	670
2013-07-01	642
2013-10-01	596
2014-01-01	535
2014-04-01	642
2014-07-01	575
2014-10-01	559
2015-01-01	565
2015-04-01	615
2015-07-01	631
2015-10-01	593
2016-01-01	563
2016-04-01	698
2016-07-01	628
2016-10-01	652
2017-01-01	567
2017-04-01	701
2017-07-01	697
2017-10-01	684
2018-01-01	625
2018-04-01	614
2018-07-01	692