Month Million Square Feet 1919-01-01 1.34000 1919-02-01 1.71000 1919-03-01 1.89000 1919-04-01 2.75000 1919-05-01 3.60000 1919-06-01 6.12000 1919-07-01 7.04000 1919-08-01 5.71000 1919-09-01 4.52000 1919-10-01 5.38000 1919-11-01 3.03000 1919-12-01 4.21000 1920-01-01 3.53000 1920-02-01 2.47000 1920-03-01 5.18000 1920-04-01 5.42000 1920-05-01 5.13000 1920-06-01 5.56000 1920-07-01 5.04000 1920-08-01 4.64000 1920-09-01 3.50000 1920-10-01 3.75000 1920-11-01 2.27000 1920-12-01 2.06000 1921-01-01 2.92000 1921-02-01 2.69000 1921-03-01 4.99000 1921-04-01 6.57000 1921-05-01 6.86000 1921-06-01 7.54000 1921-07-01 8.54000 1921-08-01 7.44000 1921-09-01 9.76000 1921-10-01 6.14000 1921-11-01 5.24000 1921-12-01 5.56000 1922-01-01 4.16000 1922-02-01 4.79000 1922-03-01 8.22000 1922-04-01 10.6100 1922-05-01 11.7800 1922-06-01 14.2200 1922-07-01 11.6500 1922-08-01 10.1200 1922-09-01 6.83000 1922-10-01 6.66000 1922-11-01 5.22000 1922-12-01 3.65000 1923-01-01 3.96000 1923-02-01 6.50000 1923-03-01 8.01000 1923-04-01 9.59000 1923-05-01 6.96000 1923-06-01 7.67000 1923-07-01 7.22000 1923-08-01 5.88000 1923-09-01 5.16000 1923-10-01 7.43000 1923-11-01 5.83000 1923-12-01 5.19000 1924-01-01 4.71000 1924-02-01 7.79000 1924-03-01 9.37000 1924-04-01 8.44000 1924-05-01 9.73000 1924-06-01 7.77000 1924-07-01 9.47000 1924-08-01 7.22000 1924-09-01 8.05000 1924-10-01 6.32000 1924-11-01 4.51000 1924-12-01 5.01000 1925-01-01 4.20000 1925-02-01 6.29000 1925-03-01 8.83000 1925-04-01 8.99000 1925-05-01 8.51000 1925-06-01 12.5400 1925-07-01 11.1000 1925-08-01 10.7600 1925-09-01 9.67000 1925-10-01 6.47000 1925-11-01 5.42000 1925-12-01 5.78000