Census Bureau has compiled all kinds of factoids about the country, then and now. Keep in mind that the U.S. was just coming out of the Great Depression in 1940 - and was only a few years from entering World War II. Some snippets:
POPULATION
1940 Population 132.2 million
2010 Population 308.7 million
1940 California population: 6.9 million
2010 California population: 37.2 million
RACE
1940
89.8% White
9.8% Black
0.4% Other
2010
72.4% White Alone
12.6% Black or African American alone
4.8% Asian Alone
0.9% American Indian & Alaskan Native alone
0.2% Some Other Race Alone
2.9% Two or More Races
Population by Hispanic or Latino Origin
16.3% Hispanic of Latino
83.7% Not Hispanic or Latino
EDUCATION
1940
5% of population with Bachelors Degree
5.5% of Males 25+who are college grads
3.8% of Females 25+ who are college grads
2010
28% of Population with Bachelors Degree
28.5% of Males 25+ who are college grads
27.9% of Females 25+ who are college grads
EARNINGS
1940 $956 Median Income for Men
2010 $33,276 Median Income for Men
1940 $592 Median Income for Women`
2010 $24,157 Median Income for Women
1940 Women earned 62 cents for each dollar a man earned
2010 Women earned 74 cents for each dollar a man earned
TOP INDUSTRIES
1940
23.4% Manufacturing
18.5% Agriculture
14.0% Retail Trade
8.9% Personal Services
7.4% Professional & Related Services
2010
23.2% Educational services, health care & social assistance
11.7% Retail Trade
10.6% Professional, scientific, management & administrative services, waste management services
10.4% Manufacturing
6.2% Construction
HOUSING
1940
$30.83 Average monthly rent, urban
$18.35, Average monthly rent, rural, non‐farm
78.9% had an outside toilet, rural‐farm
17.7% had running water, rural‐farm
31.3% had electric light, rural‐farm
2010
$855 Median monthly rent and utilities
$1496 Median monthly housing costs for mortgaged owners
99.4% had complete plumbing
97.5% had telephone service
57.1% had two or more vehicles