 Historians believe they have a high degree of falsification; formal pressure on census takers (predominantly school-teachers) was possible, and a new bilingual category was created to further complicate the results, as bilingual people (that is those who could speak both German and Polish) were classified as Germans.Some analysts have asserted that all people registering as bilingual were classified as Germans.The Polish population in this heavily Germanised city has been officially estimated at around 12–15% during this period.