U.S. Population in 2020 Marks Slowest Growth in 83 Years: Census

The U.S. population grew by only 0.1 percent, or 392,665 people, from July of 2020 to July of 2021, the lowest percentage increase since 1937, according to the U.S. Census Bureau.

Thirty-three states saw their populations increase, while 17 states and the District of Columbia saw decreases. Eleven states had losses of more than 10,000 residents. The bureau said it is "a historically large number of states to lose population in a year."

The COVID-19 pandemic, which delayed the census, is among the reasons for the slowed growth as hundreds of thousands of people have died from the virus. Other contributing factors include delayed pregnancies and immigration. During the first year of the pandemic, the growth rate fell to its lowest point in U.S. history.

"Population growth has been slowing for years because of lower birth rates and decreasing net international migration, all while mortality rates are rising due to the aging of the nation's population," demographer Kristie Wilder said. "Now, with the impact of the COVID-19 pandemic, this combination has resulted in an historically slow pace of growth."

Between 2020 and 2021, the U.S. population increased substantially due to natural increase, defined by the bureau as "the number of excess births over deaths." However, net international migration, defined as "the difference between the number of people moving into the country and out of the country," topped natural increases for the first time.

Among the data provided by the bureau, Texas, which has a population of 29,527,941, had the largest amount of annual and cumulative population growth. Texas joined Florida and Arizona as the states with the largest net domestic migration gains. Despite the influx, Florida had the highest natural decrease with 45,248 natural deaths. Pennsylvania and Ohio also saw significant numbers of natural deaths.

Between 2020 and 2021, 33 states saw population increases, primarily through domestic migration, while 17 states and the District of Columbia lost population.

States in the Mountain West saw the biggest year-over-year growth, with Idaho growing by almost 3%, and Utah and Montana each seeing population increases of 1.7%. The District of Columbia lost 2.9% of its population, while New York and Illinois lost 1.6% and 0.9% of their populations, respectively.

California remains the most populous state with 39,237,836 people, followed by Texas, Florida, New York, Pennsylvania, Illinois, Ohio, Georgia, North Carolina and Michigan.

The population estimates are derived from calculating the number of births, deaths and migration. There was a net increase of nearly 245,000 residents from international migration but only about 148,000 from natural increase.

The Associated Press contributed to this report.