The breakup of the Soviet Union brought about one of the most unexpected economic and social upheavals of the twenty-first century. Nearly overnight, economic and political systems were demolished, leaving a population confused and uncertain. The crisis not only led to widespread unemployment, wage stagnation and inflation, it also created a demographic crisis, with substantial migration and increases in mortality. The changes also led to shifts in family formation behaviour. Marriage declined, divorce increased and births outside of marriage increased. Most notably, fertility rates plunged. During the last decade of the twentieth century, the largest former Soviet Republic — Russia — witnessed one of the lowest fertility rates in the world.