Quarter	Number of Buildings
1972-01-01	21173.64252663620
1972-04-01	20859.74430238460
1972-07-01	19616.22441400300
1972-10-01	24387.47742262810
1973-01-01	21968.04649416540
1973-04-01	29366.38617960430
1973-07-01	23634.12168442410
1973-10-01	24124.28583460170
1974-01-01	23235.71239979710
1974-04-01	24585.47476407910
1974-07-01	21878.70623033990
1974-10-01	22168.45843734140
1975-01-01	20796.96465753420
1975-04-01	24636.18140030440
1975-07-01	20707.62439370880
1975-10-01	20688.30757990870
1976-01-01	18681.77354642310
1976-04-01	19881.83060375440
1976-07-01	16824.94481988840
1976-10-01	24336.77078640280
1977-01-01	19116.40185692540
1977-04-01	18363.04611872150
1977-07-01	18032.24568239470
1977-10-01	18686.60274987320
1978-01-01	20557.91908675800
1978-04-01	18181.95098934550
1978-07-01	15888.07935058350
1978-10-01	21301.61641806190
1979-01-01	13941.91036022320
1979-04-01	14463.46433282600
1979-07-01	13990.20239472350
1979-10-01	14835.31299847790
1980-01-01	14483.50552714360
1980-04-01	17711.82803348550
1980-07-01	14217.65787721970
1980-10-01	16035.61151598170
1981-01-01	15361.69617453070
1981-04-01	15728.71563673260
1981-07-01	14113.34708269910
1981-10-01	15166.11343480470
1982-01-01	13654.57275494670
1982-04-01	12768.41392186710
1982-07-01	11952.27853881280
1982-10-01	16573.82624048710
1983-01-01	13574.89089802130
1983-04-01	14523.82937595130
1983-07-01	10807.75732115680
1983-10-01	17476.88728564180
1984-01-01	11826.71924911210
1984-04-01	11288.26306443430
1984-07-01	8909.88036529680
1984-10-01	16766.99437848810
1985-01-01	11212.20311009640
1985-04-01	15683.07966412990
1985-07-01	11971.11243226790
1985-10-01	14806.09631760530
1986-01-01	10867.88090410960
1986-04-01	14328.48809639780
1986-07-01	12173.21459665140
1986-10-01	14455.97906747840
1987-01-01	14005.41438559110
1987-04-01	15135.20653272450
1987-07-01	16012.43133942160
1987-10-01	15482.42626078130
1988-01-01	15147.52100152210
1988-04-01	15125.54812582450
1988-07-01	16606.90628411970
1988-10-01	18468.56421410450
1989-01-01	16942.29446372400
1989-04-01	17927.69342770170
1989-07-01	16894.00242922370
1989-10-01	17143.67224759010
1990-01-01	15096.57290512430
1990-04-01	13756.46894774230
1990-07-01	14119.38358701170
1990-10-01	14830.96671537290
1991-01-01	11577.29089091830
1991-04-01	12658.30808320650
1991-07-01	13321.35771689500
1991-10-01	11666.14823439880
1992-01-01	11017.34475088790
1992-04-01	12002.98517503810
1992-07-01	12171.28291527140
1992-10-01	15640.82413394220
1993-01-01	10074.68423744290
1993-04-01	11401.74934550990
1993-07-01	11444.24633587010
1993-10-01	14655.42516996450
1994-01-01	12196.15331303910
1994-04-01	13477.58244850330
1994-07-01	14369.05340537800
1994-10-01	16679.10287569760
1995-01-01	17237.84171486560
1995-04-01	18247.14523592090
1995-07-01	19164.69389142570
1995-10-01	18404.09434804670
1996-01-01	15670.76519533230
1996-04-01	17370.64480974120
1996-07-01	18194.02399797060
1996-10-01	18087.78152207000
1997-01-01	16549.68022323690
1997-04-01	19328.88680872650
1997-07-01	20594.13811263320
1997-10-01	21460.98013191270
1998-01-01	24276.40574327750
1998-04-01	20611.04032470830
1998-07-01	25889.35969558600
1998-10-01	27548.19108066970
1999-01-01	29277.04591577880
1999-04-01	30040.06006088280
1999-07-01	34811.31306950790
1999-10-01	29132.16981227800
2000-01-01	30590.58925418570
2000-04-01	33804.42415017760
2000-07-01	35332.86704211060
2000-10-01	29129.75521055300
2001-01-01	31626.45339421610
2001-04-01	31930.69321156770
2001-07-01	31660.25781836630
2001-10-01	31242.53171993910
2002-01-01	27753.43222729580
2002-04-01	30288.76403855910
2002-07-01	35381.15907661090
2002-10-01	37658.12850329780
2003-01-01	33872.03299847790
2003-04-01	35963.07809233890
2003-07-01	40338.33641806190
2003-10-01	40063.07182141040
2004-01-01	39135.86475900560
2004-04-01	41219.18312734650
2004-07-01	42403.06235312020
2004-10-01	43113.19672044650
2005-01-01	43628.95564890920
2005-04-01	42942.24291831560
2005-07-01	43547.58357077620
2005-10-01	42832.62000000000
2006-01-01	42179.71169355660
2006-04-01	45948.42206595640
2006-07-01	44174.65563876200
2006-10-01	51249.92161339420
2007-01-01	40900.69715981740
2007-04-01	39437.20705428720
2007-07-01	35454.80442922370
2007-10-01	32940.96257331300
2008-01-01	27621.66666666670
2008-04-01	24053.66666666670
2008-07-01	14188.66666666670
2008-10-01	13455.66666666670
2009-01-01	7609.33333333333
2009-04-01	6883.33333333333
2009-07-01	5558.00000000000
2009-10-01	6692.66666666667
2010-01-01	5953.66666666667
2010-04-01	5996.33333333333
2010-07-01	4463.66666666667
2010-10-01	4616.33333333333
2011-01-01	5165.33333333333
2011-04-01	4626.33333333333
2011-07-01	4098.33333333333
2011-10-01	3428.66666666667
2012-01-01	3705.00000000000
2012-04-01	2910.33333333333
2012-07-01	2714.66666666667
2012-10-01	2196.66666666667
2013-01-01	2393.66666666667
2013-04-01	2569.00000000000
2013-07-01	2261.33333333333
2013-10-01	2520.00000000000
2014-01-01	2720.66666666667
2014-04-01	2728.33333333333
2014-07-01	2733.00000000000
2014-10-01	2524.66666666667
2015-01-01	3313.33333333333
2015-04-01	3870.00000000000
2015-07-01	3809.33333333333
2015-10-01	4093.66666666667
2016-01-01	5033.33333333333
2016-04-01	4895.00000000000
2016-07-01	4447.00000000000
2016-10-01	4951.00000000000
2017-01-01	5948.66666666667