was spoken, as well as the land area in which it was spoken by the majority, declined between 1790 and 1890. Polish authors before 1918 estimated the number of Poles in Prussian Upper Silesia as slightly higher than according to official German censuses. Plebiscite in Prussian Upper Silesia In the 1921 plebiscite, 40.6% of eligible voters (people over 20 years old – a minimum age that favoured the German-speaking population, whose median age was greater than that of Polish-speakers of Upper Silesia, according to censuses of 1900–1910) decided to secede from Germany and become Polish citizens. In total, over seven hundred towns and villages voted in favour of Poland, especially in the counties of Pszczyna, Rybnik, Tarnowskie Góry, Toszek-Gliwice, Strzelce Opolskie, Bytom, Katowice, Lubliniec, Zabrze, Racibórz, Olesno, Koźle and Opole. Historiography See also Silesian upraising List of Silesians People by city in Silesia External links Tomasz Kamusella. The Szlonzoks and their Language: Between Germany, Poland and Szlonzokian Nationalism The Silesian Museum: The Architecture of Identity References Slavic ethnic groups Silesia People from Silesia Bohemian people Lechites Ethnic groups in Poland Ethnic groups in the Czech Republic Ethnic groups in Germany Ethnic groups divided by international borders