E-6. Population Estimates and Components of Change by County—July 1, 2010–2019

December 2019

OFFICIAL STATE ESTIMATES

Contents

This report presents preliminary state and county population estimates for July 1, 2019, revised estimates for July 1, 2010, July 1, 2011, July 1, 2012, July 1, 2013, July 1, 2014, July 1, 2015, July 1, 2016, July 1, 2017, July 1, 2018, and components of population change.



Highlights

California’s population grew by 141,300 people between July 1, 2018 and July 1, 2019 to total 39.96 million, according to official population estimates released today by the Department of Finance. This represented a growth rate of 0.35 percent which was a further decline from our last official estimate. Our previous estimates were the lowest since 1905 when DRU’s annual population estimates begin and the trend continued. The state’s population growth rate had been below 1.0 percent since 2005. The reasons for the decline during this decade were, by order of magnitude, higher domestic out-migration, lower immigration to California, and fewer births.

The natural increase (births minus deaths) was the primary source of the state’s population growth with 452,200 births and 271,400 deaths for a natural increase of 180,800. The birth rate had declined to 11.3 births per 1,000 population from 13.8 births per 1,000 population in 2010 and reached the third lowest level since the beginning of our data in 1905. As the baby boomer generation advanced towards retirement ages, the death rate had slowly increased to 6.8 deaths per 1,000 population, up from 6.2 in 2010.

The natural increase was offset by estimated negative net migration from our state. While international migration was still a net positive, we were estimating that negative domestic out-migration was greater for the first time since 2010 resulting in negative net migration of 39,500 residents. Net migration was the total number of legal and unauthorized immigrants, and movers to California from other U.S. states or abroad, less the number of Californians who moved to another state or abroad. This marked the first time since the 2010 Census that California had more people leaving the state than moving in from abroad or other states (net migration was also negative during 1993-96 and 2005-10). California remained the top destination for legal immigration to the US with net international migration at 158,100 people in fiscal year 2018-2019. Net domestic migration was estimated at -197,600 people during the same time. Net domestic migration had been negative each year since 2011, with the estimated out-migration flow exceeding 100,000 people each year since 2015.

Since the national census on April 1, 2010, the state has grown by 2.7 million persons.

Methodology

The state and county population are independently estimated using population change models benchmarked on official decennial census counts. The state population is estimated using the Driver License Address Change method. County population proportions are estimated using the average of three separately estimated sets of proportions. The final distribution of proportions is applied to the independently estimated state control.

State Estimate. The state population is estimated using the Driver License Address Change (DLAC) Method. This composite method separately estimates the population under age 18, 18 through 64, and 65 years and older. Administrative records such as births, deaths, driver license address changes, tax return data, Medicare and Medi-Cal enrollment, immigration reports, elementary school enrollments, and group quarters population are among the data used in this method. All data used to develop these estimates are in summary tables and do not reveal the identity of any individual.

County Estimates. Most of county populations estimates result from averaging the first three methods below. We use a Vital Statistics Method in nine counties with 65,000 populations or less.

DLAC Method.A modified version of the state Driver License Address Change (DLAC) method is used for counties. County proportions of the state total result from changes in county population values for births, deaths, school enrollment, foreign and domestic migration, medical care and medical aid enrollments, and group quarters population.

Ratio-Correlation Method.This method models change in household population as a function of changes in the distributions of driver licenses, school enrollments, and housing units. Estimates of county group quarters are added.

Tax Return Method. County proportions are derived by the U.S. Census Bureau using matched federal income tax returns to estimate inter-county migration along with vital statistics, group quarters, and other information for the population aged 65 and over.

Vital Statistics Method. County population estimates result from changes in county population values for births, deaths, and group quarters population.

Data Considerations

Sources. Data used in estimation models come from administrative records of numerous state and federal departments and agencies. Timeliness and coverage in these series vary. Corrections, adjustments or estimates may be made while preparing the estimates.

Accuracy. In general, estimates become less precise as the time from the last census increases. Data and models used to produce population estimates are subject to both measurement and non-measurement errors. This results in imperfect correlation between the data used to estimate the population and actual population change. The data and estimating models have been thoroughly tested with decennial census results that provide benchmarks for the estimates series. Data and methods are further refined and modified throughout the decade.

Acknowledgments

Phuong Nguyen produced the state and county estimates and prepared this report. Andres Gallardo produced the birth and death data. Douglas Kuczynski and John Boyne collected and prepared the group quarters data. Alex Alvarado produced the school enrollment projections. John Boyne validated input data, formulas, and methodologies used in the current state and county estimates series.



Suggested Citation

State of California, Department of Finance, E-6. Population Estimates and Components of Change by County, July 1, 2010-2019. Sacramento, California, December 2019.