Month Million Square Feet 1919-01-01 4.77000 1919-02-01 2.84000 1919-03-01 5.37000 1919-04-01 7.01000 1919-05-01 11.2300 1919-06-01 12.4000 1919-07-01 14.8600 1919-08-01 18.1900 1919-09-01 14.1500 1919-10-01 20.3100 1919-11-01 20.9900 1919-12-01 19.4300 1920-01-01 18.7800 1920-02-01 13.7100 1920-03-01 22.7000 1920-04-01 13.4300 1920-05-01 10.9700 1920-06-01 10.4100 1920-07-01 6.67000 1920-08-01 6.72000 1920-09-01 8.21000 1920-10-01 5.00000 1920-11-01 5.23000 1920-12-01 3.56000 1921-01-01 2.27000 1921-02-01 1.78000 1921-03-01 2.33000 1921-04-01 3.46000 1921-05-01 3.42000 1921-06-01 3.40000 1921-07-01 2.57000 1921-08-01 2.19000 1921-09-01 2.62000 1921-10-01 3.94000 1921-11-01 4.16000 1921-12-01 2.54000 1922-01-01 2.79000 1922-02-01 2.24000 1922-03-01 3.97000 1922-04-01 4.75000 1922-05-01 5.82000 1922-06-01 4.16000 1922-07-01 6.71000 1922-08-01 10.1100 1922-09-01 3.96000 1922-10-01 7.04000 1922-11-01 6.16000 1922-12-01 4.12000 1923-01-01 3.80000 1923-02-01 4.62000 1923-03-01 7.36000 1923-04-01 5.82000 1923-05-01 8.42000 1923-06-01 4.01000 1923-07-01 3.69000 1923-08-01 3.14000 1923-09-01 3.95000 1923-10-01 3.68000 1923-11-01 4.60000 1923-12-01 4.57000 1924-01-01 2.65000 1924-02-01 3.71000 1924-03-01 4.12000 1924-04-01 4.18000 1924-05-01 3.54000 1924-06-01 2.77000 1924-07-01 2.32000 1924-08-01 2.58000 1924-09-01 3.17000 1924-10-01 3.33000 1924-11-01 2.93000 1924-12-01 4.07000 1925-01-01 3.69000 1925-02-01 2.41000 1925-03-01 3.99000 1925-04-01 5.47000 1925-05-01 4.69000 1925-06-01 3.14000 1925-07-01 4.17000 1925-08-01 4.21000 1925-09-01 7.61000 1925-10-01 6.06000 1925-11-01 6.49000 1925-12-01 4.42000