The year 2026 marks the 235th anniversary of the adoption of the 3rd of May Constitution. The Constitution was adopted by the Four-Year Sejm, known as the Great Sejm (1788-1792). It was the first constitution in Europe and the second in the world, after the Constitution of the United States. 

On 22 June 1789, the Constitution was adopted, on the basis of which the first census was conducted in the Polish lands. The census recorded the population figures and its socio-occupational structure.

The last census in Poland was conducted in 2021.