While some people live by subsistence, the vast majority of people in the world depend on some exchange of goods and services for survival. Many also depend on the economic system for jobs and income. Economic insecurity can lead to unemployment, poverty, and hunger, and often motivates migration, increases inequality, and even encourages violent conflict. The UN estimates that 1.5 billion people—about a quarter of the world's population—live on $1 or less a day.