MOSCOW, September 18 (RIA Novosti) - Russia's next national census, originally scheduled for October 2010, has been postponed to 2013 due to the economic crisis, a spokesman for Russian statistics service Rosstat said on Friday.

"We hope the census will be conducted in October 2013, because October is the best month for a census in Russia," Alexander Surinov said in an interview on Russian Vesti TV news channel.

The last census, conducted in 2002, showed the population in the country was 145.274 million people. According to Rosstat estimates, there were about 141.9 million people living in Russia in the first half of 2009, a fall of about 133,700 year-on-year.

Surinov explained how the population was calculated in the absence of a fresh count.

"We add to the last census figure the number of those born in the period, and take away those who died. We add those who arrived, and take away those who left," he said.

"If you speak about births and deaths, the figure is quite reliable. But if you speak about arrivals and departures there can be various issues, especially in our country" he added.

According to the Russian Federal Migration Service, there are about 15 million immigrants currently living in Russia, the majority illegally. Most of them are from former Soviet republics.

Alexander Surinov said some 2 billion rubles ($66 million) of 18 billion expected to be allocated for the census have been already spent on the development of census methods, the education of census takers, and equipment. He said more than 10 billion rubles would be spent on census takers' salaries, adding the census would pay special attention to the living conditions of Russian residents.