Bestselling books of the 1920s and 1930s

Some historical data, from Publisher's Weekly

Bestselling books (fiction and non-fiction), covering the years 1920 - 1929:  http://www.caderbooks.com/best20.html

Bestselling books (fiction and non-fiction), covering the years 1930 - 1939:    http://www.caderbooks.com/best30.html