The earliest exact census figures on ethnolinguistic or national structure (') of the Prussian-ruled part of Upper Silesia, come from year 1819. The last pre-WW1 general census figures available, are from 1910 (if not including the 1911 census of school children - ' - which revealed a higher percent of Polish-speakers among school children than the 1910 census among the general populace). Figures (see table 1) show that large demographic changes took place between 1819 and 1910, with the region's total population quadrupling, the percent of German-speakers increasing significantly, and that of Polish-speakers declining considerably. Also the total land area in which Polish language was spoken, as well as the land area in which it was spoken by the majority, declined between 1790 and 1890. United States Immigration Commission in 1911 classified Polish-speaking Silesians as ethnic Poles.