Month	Millions Of Books
1919-01-01	5.60000
1919-02-01	6.33000
1919-03-01	7.92000
1919-04-01	7.14000
1919-05-01	9.17000
1919-06-01	9.75000
1919-07-01	10.9800
1919-08-01	12.9300
1919-09-01	13.7900
1919-10-01	13.3000
1919-11-01	11.1700
1919-12-01	12.4700
1920-01-01	13.6000
1920-02-01	10.9900
1920-03-01	12.3400
1920-04-01	13.3000
1920-05-01	11.2800
1920-06-01	10.8100
1920-07-01	9.15000
1920-08-01	8.32000
1920-09-01	9.38000
1920-10-01	7.58000
1920-11-01	4.63000
1920-12-01	3.72000
1921-01-01	5.42000
1921-02-01	4.54000
1921-03-01	5.36000
1921-04-01	8.30000
1921-05-01	6.98000
1921-06-01	7.68000
1921-07-01	7.92000
1921-08-01	9.19000
1921-09-01	8.52000
1921-10-01	10.6000
1921-11-01	9.38000
1921-12-01	8.08000
1922-01-01	10.1600
1922-02-01	8.80000
1922-03-01	9.65000
1922-04-01	10.3200
1922-05-01	10.2300
1922-06-01	11.0900
1922-07-01	10.5400
1922-08-01	12.0900
1922-09-01	12.2400
1922-10-01	13.4000
1922-11-01	11.1200
1922-12-01	9.71000
1923-01-01	12.2900
1923-02-01	11.4400
1923-03-01	11.5300
1923-04-01	11.1600
1923-05-01	12.3500
1923-06-01	11.4900
1923-07-01	11.3000
1923-08-01	10.9000
1923-09-01	11.3700
1923-10-01	12.1800
1923-11-01	11.2600
1923-12-01	8.85000
1924-01-01	11.4100
1924-02-01	10.9500
1924-03-01	11.7300
1924-04-01	10.4700
1924-05-01	11.0200
1924-06-01	11.0000
1924-07-01	9.77000
1924-08-01	11.6500
1924-09-01	11.8300
1924-10-01	12.2700
1924-11-01	10.5700
1924-12-01	9.19000
1925-01-01	12.0300
1925-02-01	11.4900
1925-03-01	12.4800
1925-04-01	11.3400
1925-05-01	12.2300
1925-06-01	12.3600
1925-07-01	11.7700
1925-08-01	12.1500
1925-09-01	12.5600
1925-10-01	13.5000
1925-11-01	11.6900
1925-12-01	10.3000
1926-01-01	11.7900
1926-02-01	10.5600
1926-03-01	13.2800
1926-04-01	11.4700
1926-05-01	12.2500
1926-06-01	12.9500
1926-07-01	11.6400
1926-08-01	13.2900
1926-09-01	12.6800
1926-10-01	11.7200
1926-11-01	11.0900
1926-12-01	10.2400
1927-01-01	12.9200
1927-02-01	11.6300
1927-03-01	12.0800
1927-04-01	11.0400
1927-05-01	12.2300
1927-06-01	11.7900
1927-07-01	12.2300
1927-08-01	12.7400
1927-09-01	12.2800
1927-10-01	13.8500
1927-11-01	12.1300
1927-12-01	10.6700
1928-01-01	12.3300
1928-02-01	12.3300
1928-03-01	13.1900
1928-04-01	11.8000
1928-05-01	12.1600
1928-06-01	12.7100
1928-07-01	12.1000
1928-08-01	12.5400
1928-09-01	11.8400
1928-10-01	13.9600
1928-11-01	12.7300
1928-12-01	11.1200
1929-01-01	12.8600
1929-02-01	11.7600
1929-03-01	12.3200
1929-04-01	12.7200
1929-05-01	12.7500
1929-06-01	12.3300
1929-07-01	13.7400
1929-08-01	12.8400
1929-09-01	12.9800
1929-10-01	13.8300
1929-11-01	12.1100
1929-12-01	9.83000
1930-01-01	13.0300
1930-02-01	11.6800
1930-03-01	12.3500
1930-04-01	11.6600
1930-05-01	11.7300
1930-06-01	12.6900
1930-07-01	10.9000
1930-08-01	11.0300
1930-09-01	11.6500
1930-10-01	12.2200
1930-11-01	11.0500
1930-12-01	9.46000
1931-01-01	10.7400
1931-02-01	10.0500
1931-03-01	11.2000
1931-04-01	10.2800
1931-05-01	11.5900
1931-06-01	10.5100
1931-07-01	10.3200
1931-08-01	10.5100
1931-09-01	10.2800
1931-10-01	10.6600
1931-11-01	9.97000
1931-12-01	8.10000
1932-01-01	9.26000
1932-02-01	8.65000
1932-03-01	8.91000
1932-04-01	9.43000
1932-05-01	8.49000
1932-06-01	8.91000
1932-07-01	8.40000
1932-08-01	7.88000
1932-09-01	8.58000
1932-10-01	10.1900
1932-11-01	8.48000
1932-12-01	7.65000
1933-01-01	9.74000
1933-02-01	7.91000
1933-03-01	7.40000
1933-04-01	9.90000
1933-05-01	10.3800
1933-06-01	12.9300
1933-07-01	13.0800
1933-08-01	13.3600
1933-09-01	10.9600
1933-10-01	9.70000
1933-11-01	9.34000
1933-12-01	11.2000
1934-01-01	9.43000
1934-02-01	9.73000
1934-03-01	12.1400
1934-04-01	9.78000
1934-05-01	11.6500
1934-06-01	11.1300
1934-07-01	11.4200
1934-08-01	11.1300
1934-09-01	11.8000
1934-10-01	14.6000
1934-11-01	11.5600
1934-12-01	11.2300
1935-01-01	11.1300
1935-02-01	11.6900
1935-03-01	12.4600
1935-04-01	11.3400
1935-05-01	11.7300
1935-06-01	12.2200
1935-07-01	12.7300
1935-08-01	12.3000
1935-09-01	12.3900
1935-10-01	14.9600
1935-11-01	13.3100
1935-12-01	13.0400