 A second obstacle, partly related to the sheer vastness and geographical diversity of the Russian landmass, was the sizable number of "mono-industrial" regional economies (regions dominated by a single industrial employer) that Russia inherited from the Soviet Union.The concentration of production in a relatively small number of big state enterprises meant that many local governments were entirely dependent on the economic health of a single employer; when the Soviet Union collapsed and the economic ties between Soviet republics and even regions were severed, the production in the whole country dropped by more than fifty percent.Roughly half of Russia's cities had only one large industrial enterprise, and three fourths had no more than four.