Russia’s population declined by nearly 3.4 million over the past decade, according to census figures released Monday, adding to fears that an aging and decreasing population will sap economic growth. A census carried out in October 2010 showed that the population had fallen to 142.9 million, from 145.2 million in 2002, when the previous census was taken, and from 146.3 million in 2001, according to Russia’s Federal Statistics Service. Russia is expected to lose an estimated one million workers every year until 2017.