Reference 1: Population.
Reference 2: New York, Pennsylvania, Illinois, Ohio, Texas, Massachusetts, Michigan, California, Missouri, New Jersey, Indiana, Georgia, Wisconsin, North Carolina, Kentucky, Iowa, Minnesota, Alabama, Tennessee, Virginia, Oklahoma, Louisiana, Mississippi, Kansas, Arkansas, South Carolina, West Virginia, Maryland, Connecticut, Washington, Nebraska, Florida, Colorado, Oregon, Maine, North Dakota, South Dakota, Rhode Island, Montana, Utah, New Hampshire, District of Columbia, Idaho, New Mexico, Vermont, Arizona, Delaware, Wyoming and Nevada.
Source: http://en.wikipedia.org/wiki/1920_United_States_Census
Reference 2: New York, Pennsylvania, Illinois, Ohio, Texas, Massachusetts, Michigan, California, Missouri, New Jersey, Indiana, Georgia, Wisconsin, North Carolina, Kentucky, Iowa, Minnesota, Alabama, Tennessee, Virginia, Oklahoma, Louisiana, Mississippi, Kansas, Arkansas, South Carolina, West Virginia, Maryland, Connecticut, Washington, Nebraska, Florida, Colorado, Oregon, Maine, North Dakota, South Dakota, Rhode Island, Montana, Utah, New Hampshire, District of Columbia, Idaho, New Mexico, Vermont, Arizona, Delaware, Wyoming and Nevada.
Source: http://en.wikipedia.org/wiki/1920_United_States_Census
