An annual estimate of spatially disaggregated populations: Spain, 1900-2011

Long-term population estimates are usually based on decennial (or roughly decennial), census-type data, especially those that go beyond the aggregate or national level. The lack of annual population datasets, however, restricts the range of analysis and therefore our knowledge of populations' behaviour over time. This paper contributes to this scant literature by providing two new long-term, annually and spatially disaggregated population estimates for Spain, a key case study. We use a set of official sources and propose a straightforward method to estimate Spanish annual populations at two levels of spatial disaggregation, the provinces (NUTS III) and their capital cities (a selection of LAU II/NUTS V), between 1900 and 2011. For the cities, our estimates account for changes in boundaries. Our proposed method is especially suitable for countries with a lack of long-term, systematic, historical migration statistics, a common issue. To test the robustness of our estimates, some comparisons are made with previous more aggregated-level or decennial census-based estimates, and a preliminary analysis of the evolution of disaggregated Spanish population is presented.