Czechs have sent two million filled-in population and housing census forms to the organizing Czech Statistical Office (CSU), CSU chairman Marek Rojíček told journalists Monday. From the towns with over 10,000 population, the residents of Neratovice, Central Bohemia, and Most, north Bohemia, have been the most active. The online census started on March 27 and it will end on May 11. Czechs may also send paper census forms until April 17. The two million forms mean that roughly four million people have been counted, Rojíček said. During Easter, the number of forms sent in increased by over 600,000, he added. The Czech Republic has about 10.5 million inhabitants In Neratovice, there are over 46 filled-in forms per 100 flats, followed by Most and Kolin with about 45 forms per 100 flats. The largest Czech cities Prague and Brno have proven similar with regard to their residents' participation in the census; in both towns, residents sent 42.1 forms per 100 flats.