Month Million Square Feet 1919-01-01 13.1000 1919-02-01 15.1000 1919-03-01 25.7000 1919-04-01 39.2000 1919-05-01 51.0000 1919-06-01 65.5000 1919-07-01 65.7000 1919-08-01 62.2000 1919-09-01 50.0000 1919-10-01 68.5000 1919-11-01 51.8000 1919-12-01 49.4000 1920-01-01 41.9000 1920-02-01 34.7000 1920-03-01 54.6000 1920-04-01 51.2000 1920-05-01 42.1000 1920-06-01 36.9000 1920-07-01 28.0000 1920-08-01 28.0000 1920-09-01 26.3000 1920-10-01 25.3000 1920-11-01 19.4000 1920-12-01 13.7000 1921-01-01 15.4000 1921-02-01 16.9000 1921-03-01 26.7000 1921-04-01 34.5000 1921-05-01 35.4000 1921-06-01 35.1000 1921-07-01 31.6000 1921-08-01 35.1000 1921-09-01 41.4000 1921-10-01 40.4000 1921-11-01 37.5000 1921-12-01 34.9000 1922-01-01 30.0000 1922-02-01 29.9000 1922-03-01 51.8000 1922-04-01 57.7000 1922-05-01 59.4000 1922-06-01 60.4000 1922-07-01 51.6000 1922-08-01 52.9000 1922-09-01 43.7000 1922-10-01 46.6000 1922-11-01 46.6000 1922-12-01 39.5000 1923-01-01 38.3000 1923-02-01 41.1000 1923-03-01 64.8000 1923-04-01 65.2000 1923-05-01 60.0000 1923-06-01 45.6000 1923-07-01 41.8000 1923-08-01 39.6000 1923-09-01 38.9000 1923-10-01 53.9000 1923-11-01 51.0000 1923-12-01 47.8000 1924-01-01 48.8000 1924-02-01 47.6000 1924-03-01 67.7000 1924-04-01 62.9000 1924-05-01 57.2000 1924-06-01 47.1000 1924-07-01 39.1000 1924-08-01 41.6000 1924-09-01 43.2000 1924-10-01 47.2000 1924-11-01 48.4000 1924-12-01 46.7000 1925-01-01 41.6000 1925-02-01 37.9000 1925-03-01 64.1000 1925-04-01 72.1000 1925-05-01 68.2000 1925-06-01 66.1000 1925-07-01 67.4000 1925-08-01 77.0000 1925-09-01 67.8000 1925-10-01 67.3000 1925-11-01 66.6000 1925-12-01 63.5000