Month Million Square Feet 1919-01-01 2.49000 1919-02-01 3.93000 1919-03-01 5.56000 1919-04-01 9.11000 1919-05-01 9.32000 1919-06-01 15.7200 1919-07-01 12.1700 1919-08-01 10.7500 1919-09-01 8.92000 1919-10-01 13.9100 1919-11-01 8.54000 1919-12-01 9.48000 1920-01-01 7.32000 1920-02-01 8.67000 1920-03-01 10.1800 1920-04-01 10.8400 1920-05-01 8.40000 1920-06-01 9.50000 1920-07-01 7.33000 1920-08-01 5.00000 1920-09-01 5.87000 1920-10-01 4.93000 1920-11-01 3.61000 1920-12-01 2.34000 1921-01-01 3.26000 1921-02-01 3.28000 1921-03-01 4.38000 1921-04-01 4.80000 1921-05-01 5.59000 1921-06-01 5.41000 1921-07-01 6.06000 1921-08-01 6.94000 1921-09-01 7.16000 1921-10-01 7.99000 1921-11-01 5.16000 1921-12-01 4.58000 1922-01-01 4.81000 1922-02-01 6.26000 1922-03-01 8.95000 1922-04-01 10.4200 1922-05-01 9.84000 1922-06-01 10.2900 1922-07-01 8.78000 1922-08-01 7.79000 1922-09-01 9.07000 1922-10-01 6.87000 1922-11-01 6.43000 1922-12-01 5.71000 1923-01-01 5.87000 1923-02-01 7.03000 1923-03-01 9.89000 1923-04-01 10.4000 1923-05-01 9.78000 1923-06-01 8.39000 1923-07-01 7.09000 1923-08-01 6.25000 1923-09-01 6.97000 1923-10-01 7.58000 1923-11-01 6.92000 1923-12-01 7.43000 1924-01-01 6.65000 1924-02-01 7.96000 1924-03-01 10.0100 1924-04-01 7.95000 1924-05-01 9.24000 1924-06-01 7.83000 1924-07-01 6.28000 1924-08-01 6.85000 1924-09-01 7.23000 1924-10-01 8.55000 1924-11-01 8.96000 1924-12-01 7.21000 1925-01-01 9.67000 1925-02-01 5.38000 1925-03-01 9.86000 1925-04-01 10.1700 1925-05-01 12.1400 1925-06-01 11.7700 1925-07-01 10.7600 1925-08-01 14.3900 1925-09-01 11.2000 1925-10-01 9.51000 1925-11-01 9.63000 1925-12-01 9.57000