Russia's population has shrunk by more than half a million people this year, dipping to 143 million, the federal statistics agency said Friday, Associated Press reported. Russia's population _ the largest in Europe _ has been declining steadily since the 1991 breakup of the Soviet Union, with increased poverty, alcoholism, emigration and degradation of the health care system blamed for reducing birth rates and life expectancy. Since the beginning of the year, the population went down by 506,400, the agency said on its Web site. U.N. experts have urged Russian authorities to boost social spending to improve health care and prevent the population decline. In a U.N. Development Program report released this week, demographers predicted that Russia's population will fall to 100 million by 2050, and could even drop to 80 million. The United Nations urged Russian authorities to change its strict immigration policy to provide incentives for educated, skilled migrants from former Soviet republics and other countries to move to Russia.