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Oregon -- Population -- Statistics, Demographic surveys -- Oregon


This report provides population estimates for Oregon, its counties, and cities for the years 1980 through 1996. As mandated by Oregon law (ORS 190.510 to 190.610), the Center for Population Research and Census at Portland State University, acting on behalf of the State Board of Higher Education, annually estimates the July 1 population for each county and incorporated city in Oregon. These population estimates are used in the allocation of certain state tax revenues to cities and counties.

Population figures presented in this report represent all the people who usually reside in the area designated. This includes people living in correctional institutions, nursing homes, and college dormitories. College students are considered residents of the place where they live while attending college. Seasonal populations, such as those living in summer homes, are considered residents of the place they consider their usual residence.

Population estimates are developed as accurately as possible from standard and tested methods. The specific procedures used depend on the availability of state and local data. State estimates for Oregon are developed by a component method. The population ages 64 and under is developed from vital events (i.e., births and deaths) and an estimate of net migration based on school-aged migration. Medicare data are used to estimate the population ages 65 and older. County population estimates are determined primarily by the ratio correlation method. This method relates the change in population since the last census to the changes in a set of symptomatic data. The current equation contains school enrollment, state tax returns, voter registration, and births. Changes in the symptomatic data for each county are tracked annually since the last census to estimate the county's population. County population estimates based on the component method, and changes in housing stock since the last census are also considered, although substantially less weight is given to these estimates than that of the ratio correlation method.

City population estimates are determined by the housing unit method. Each year, cities report to the Center the changes in their housing stock and the count of persons residing in group quarter facilities (e.g., correctional facilities, college dormitories, and nursing homes). The Center adds in any population and housing changes owing to annexations. The 1990 U.S. Decennial Census provides benchmark data for each city on the number of housing units, the average number of persons per housing unit, and the number of persons residing in group quarter facilities. These data are updated annually thereby allowing for an accurate estimate of the city's population.


At the time these reports were compiled, the Population Research Center was known as the Center for Population Research and Census, School of Urban and Public Affairs, Portland State University.

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