East Prussia and parts of West Prussia were in favor of remaining part of Germany. The Saar region was placed under the control of the League of Nations for fifteen years before a referendum was to be held there. The former Imperial Territory of Alsace–Lorraine, which had been effectively under Prussian administration, was ceded to France without a vote. The annexation of the Free State of Waldeck-Pyrmont was the one Prussian territorial addition during the Weimar Republic. The Pyrmont district made the first step after a referendum in 1921. The rest of the state followed in 1929. The loss of territory had considerable negative economic and financial consequences for the Prussian state, including the costs of repatriation and provision for state employees. Under the Ministry of Justice alone, 3,500 civil servants and employees were affected. Population After 1918 the population did not increase as rapidly as it had before the war. In addition to the continuation of the demographic transition of modern industrial societies to lower birth rates, the losses of the First World War were also a factor. The large population movements within Prussia slowed. In contrast to the period before 1914, more people were moving into Prussia from foreign countries than were emigrating. In-migration from ceded territories along with increasing immigration, especially from eastern Europe, both played a role. There were also major differences in population density across Prussia. In 1925 East Prussia had an average of 60.9 inhabitants per square kilometer, while the Rhine Province had 295.6. Because of the extent of its low population rural regions, Prussia had a density of 130.7 per square kilometer, which was below average among the German states. The Free State of Saxony, by way of contrast, had 333 inhabitants per km2. Settlement patterns and urban growth Urbanization and urban growth lost momentum compared to the pre-1914 period. Population increases in larger cities were caused not so much by in-migration as by incorporation. This was the case with the formation of Greater Berlin in 1920, when 7 cities, 56 rural communities and 29 estate districts were incorporated. Even more extensive and consequential for the formation of large cities were the municipal reforms in the Ruhr region at the end of the 1920s. There were still considerable geographical differences in the extent of urbanization. While in East Prussia more than 60% of the inhabitants lived in village communities in 1925, in the