"Statelessness exists for a multitude of different reasons around the world; chunks of a population can become stateless overnight when state boundaries are redrawn; others are stateless because of discrimination against particular ethnic or religious groups. The UNHCR believes a stateless baby is born every 10 minutes. The dissolution of the Soviet Union in 1991 left large numbers stateless; more than 370,000 people, many of them ethnic Russians, still lack a nationality in Estonia and Latvia."

http://www.theguardian.com/world/2014/nov/04/un-refugee-agency-global-campaign-statelessness