Month Million Square Feet 1919-01-01 1.16000 1919-02-01 0.580000 1919-03-01 1.39000 1919-04-01 1.58000 1919-05-01 2.46000 1919-06-01 4.53000 1919-07-01 4.98000 1919-08-01 4.65000 1919-09-01 3.37000 1919-10-01 3.95000 1919-11-01 2.13000 1919-12-01 2.86000 1920-01-01 2.74000 1920-02-01 1.91000 1920-03-01 4.01000 1920-04-01 4.22000 1920-05-01 4.07000 1920-06-01 4.38000 1920-07-01 3.73000 1920-08-01 3.52000 1920-09-01 2.70000 1920-10-01 2.90000 1920-11-01 1.60000 1920-12-01 1.22000 1921-01-01 2.31000 1921-02-01 1.92000 1921-03-01 3.76000 1921-04-01 4.77000 1921-05-01 5.48000 1921-06-01 5.35000 1921-07-01 6.20000 1921-08-01 5.52000 1921-09-01 6.90000 1921-10-01 4.21000 1921-11-01 3.82000 1921-12-01 4.43000 1922-01-01 2.96000 1922-02-01 3.48000 1922-03-01 6.33000 1922-04-01 8.41000 1922-05-01 7.92000 1922-06-01 9.59000 1922-07-01 8.85000 1922-08-01 7.36000 1922-09-01 4.42000 1922-10-01 4.63000 1922-11-01 3.48000 1922-12-01 3.04000 1923-01-01 2.87000 1923-02-01 4.83000 1923-03-01 5.60000 1923-04-01 6.76000 1923-05-01 4.71000 1923-06-01 5.33000 1923-07-01 5.27000 1923-08-01 4.22000 1923-09-01 3.79000 1923-10-01 5.57000 1923-11-01 4.53000 1923-12-01 4.18000 1924-01-01 3.50000 1924-02-01 6.09000 1924-03-01 6.56000 1924-04-01 6.02000 1924-05-01 7.40000 1924-06-01 5.42000 1924-07-01 7.21000 1924-08-01 5.11000 1924-09-01 5.44000 1924-10-01 4.33000 1924-11-01 3.25000 1924-12-01 3.98000 1925-01-01 2.73000 1925-02-01 4.28000 1925-03-01 6.56000 1925-04-01 6.10000 1925-05-01 5.64000 1925-06-01 9.44000 1925-07-01 7.48000 1925-08-01 6.58000 1925-09-01 7.31000 1925-10-01 4.47000 1925-11-01 3.73000 1925-12-01 4.49000