In a 1947 report, the Census Bureau noted a “huge and steady increase” in the post-World War II birth rate.

A year later, the Census Bureau reported that “the primary factor in the rapid rate of growth of the population in recent years has been the tremendous postwar rise in the birth rate, which is due very largely to the demobilization of men from the armed forces.”

These estimates of rapid growth in the birth rate were the first signs of the baby boom, the famous period of increased fertility that would last until the mid-1960s, as detailed in a 1965 report on national population estimates.

This early look at the baby boom comes from the Census Bureau’s P25 series of publications on population estimates and projections.

The complete series of P25 reports is now posted on census.gov, and offers historical insight into the nation’s demographic transformation over seven decades.

In their early years, the P25 reports were used primarily to disseminate population estimates and projections data. As data distribution moved to electronic media and the internet, the P25 reports have served as a platform for Census Bureau research on population estimates and projections.

The series contains over 1,000 reports stretching from 1947 to the present. With population estimates at levels ranging from the local to the national, projections of future population trends and more, the publications are a rich resource for those interested in America’s demographic past, present and future.

Some other highlights include:

• A 1947 report estimated that 1 in 10 civilians in the United States was a World War II veteran.
• In 1956, the Census Bureau projected a 75% increase in the college-age population by 1973 as the baby boomers reached young adulthood. The projection was very close to the actual increase of 76%.
• Alaska’s statehood in January 1959 added an estimated 167,000 to the U.S. civilian population, and Hawaii’s statehood in August of that year added more than 600,000.
• Metro-area population estimates published in 1965 show Los Angeles surpassing Chicago in the early 1960s to become the nation’s second-largest metropolitan area.
• A set of population projections published in 1975 projected a population between 252 million and 342 million in 2015, depending on fertility trends in the ensuing decades. The Census Bureau’s most recent population estimates show the July 1, 2015, population at 321 million.
• In the 1980s, the Census Bureau began producing population estimates by Hispanic origin for states and metropolitan areas in addition to other characteristics such as age, sex, and race.
• A 1984 report used alternate assumptions about future levels of fertility, life expectancy and migration to project the U.S. population nearly 100 years into the future. The projections for 2080 range from 191 million in the low scenario – 138 million lower than the current population of 329 million – to 531 million in the high scenario.
• As data dissemination moved online in the 1990s and 2000s, the P25 publications shifted to coverage of more specialized topics such as population dynamics in the Great Plains region. That 2009 report found overall population growth in metropolitan and micropolitan statistical areas coupled with population decline in more sparsely populated Plains counties.

Peruse the complete series of P25 reports on the Census Bureau Library’s website.

Jack Byerly and Demetric Sewell are demographer-statisticians in the Estimates and Projections area of the Census Bureau’s Population Division.