Nikolai Ryzhkov, the former head of the Soviet government, has died at the age of 94, Valentina Matviyenko, chairwoman of the Russian Federation Council, announced in Moscow on Wednesday. Ryzhkov stopped working as a senator in October in the Federation Council, which is the upper house of Russia’s parliament, “prematurely,” the newspaper Vedomosti reported at the time. He had been a senator for two decades. In the 1980s, Ryzhkov was the last chairman of the Council of Ministers of the Soviet Union led by the former head of the Communist Party, Mikhail Gorbachev. From 1985, he played a key rol…