ByWilliam R. Emmons
In recent years, U.S. population growth has slowed significantly due to falling birth rates, rising death rates and fewer immigrants coming into the country.See Emmons, Bill, “U.S. Population Growth Slowing to a Crawl,” On the Economy, Feb. 2020, https://www.stlouisfed.org/on-the-economy/2020/february/us-population-growth-slowing-crawl. Similar to the rest of the nation, population growth rates in all seven states within the Eighth District (Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee) have recently declined (see Figure 1).
Differences in migration rates (domestic and international), rather than divergent trends in birth or death rates, are the largest source of variation in population growth among the district’s seven states. More precisely, relatively low rates of inward net migration are the main reason Eighth District states grow more slowly than the U.S. as a whole.
Figure 1 shows that beginning in 2012, more people have moved out of Eighth District states than moved in.
SOURCE: Census Bureau and author’s calculations.
NOTES: The chart shows the total population growth rate in each year of the U.S. and the seven states in the Eighth District as well as the two components of population growth for each—natural increase and net migration. For Eighth District states, net migration is international migration plus domestic migration, which is inbound minus outbound changes of residence within the U.S.
Given the long-term slowing of natural population increase (i.e., births minus deaths), migration trends are becoming increasingly important in determining which counties, metro areas and states gain and lose population. Historically, our district’s states have not always been deemed areas of peak migration; however, areas within Tennessee have attracted large numbers of domestic migrants, while Illinois has been a destination for international migration.
With advantages like a low cost of living, Eighth District state populations may be bolstered by migration in the future.
Population in a particular place grows or declines for two reasons:
For entities smaller than the nation as a whole, net migration is divided between net domestic migration (inward minus outward moves within the U.S.) and net international migration (immigration into the area from outside the U.S. minus emigration from the place to somewhere outside the U.S).
The sources of recent individual state population slowing differ significantly.
Additionally, some trends have worked in favor of Eighth District state population growth:
When all sources of change are considered, five states within the Eighth District continue to grow more slowly than the nation (Arkansas, Illinois, Kentucky, Mississippi and Missouri), while two states are growing faster than the nation (Indiana and Tennessee).
The easiest way to see how various aspects of natural increase and net migration contribute to a state’s total population growth is to display them relative to the nation as a whole.
In other words, each factor can be shown contributing more to the state’s population growth in a given year than it does at the national level or less. The sum of the contributing factors is the annual difference between the state’s and the nation’s population growth rates.
Figures 2-8 display features of each Eighth District state’s developments from 2001-2019, summarized below.
Arkansas (Figure 2). Domestic migration was a major contributor to above-average population growth in the mid-2000s, especially in the northwest part of the state, but it subsided after 2011. Natural increase has been slowing growth relative to the U.S. throughout the period. International migration also has been weaker than the national average, slowing population growth.
This information applies to charts 2-8.
SOURCE: Census Bureau and author’s calculations.
NOTES: The chart shows how much and why a state’s population growth rate in each year differed from the national growth rate. The line shows the difference between the state’s total population growth rate and the national population growth rate. The columns show the contributions to this growth rate difference of four factors: birth rates, death rates, domestic migration and international migration. In each case, the rate of the factor is expressed relative to its corresponding national rate. A column shown above zero means that factor contributed more to the state’s growth rate than the factor did to the national rate and vice versa for columns shown below zero. These four sources of relative population growth sum to the growth-rate difference shown by the solid line.
Illinois (Figure 3). The dominant factor throughout the period is negative domestic migration, which became even more negative after 2010. Natural increase was close to the national average throughout the period. International migration changed from a small positive to a small negative over time, relative to the U.S. as a whole.
Indiana (Figure 4). Both domestic and international migration changed from being small negative to small positive factors over time. Natural increase moved from being a minor negative factor to approximately neutral by the end of the period. The result is that Indiana’s population growth has recently exceeded the national average.
Kentucky (Figure 5). Domestic migration was a significant factor offsetting the negative influence of the natural increase in the 2000s, but became a minor detractor after 2011. Natural increase and international migration remained negative contributors throughout the entire period, pushing the state’s population growth below the national average.
Mississippi (Figure 6). The only factor that contributed positively in every year was the birth rate; but, in most years, the overall rate of natural increase subtracted from growth due to above-average death rates. Hurricane Katrina caused a large, one-time loss of population through outward domestic migration. Total net migration (domestic and international) was negative in every year, largely causing the state’s below-average population growth.
Missouri (Figure 7). Above-average domestic migration contributed positively in the mid-2000s but reversed after 2007, placing downward pressure on the growth rate. Natural increase and international migration have been negative contributors throughout the period.
Tennessee (Figure 8). Domestic migration was above the national average in every year, with cyclical peaks in 2006 and 2017. All other factors contributed negatively in virtually every year. Without the contribution of domestic migration, population growth would have been significantly below the national average throughout the period; yet, it was above-average.
Due to declining birth rates and increasing death rates, the amount of natural population increase is slowing nationwide and in each of our District states. The most important contributors to population growth or decline in particular locations will be migration patterns, both domestic and international.
While states in the Eighth District generally have not been net attractors of migrants, Tennessee and a few other states have periodically been exceptions to this rule. Desirable features such as our low cost of living may help some localities resist the population growth slowdown that is underway.
William R. Emmons is an assistant vice president and economist at the Federal Reserve Bank of St. Louis and the lead economist for the Bank's Center for Household Financial Stability.