For statistical purposes (e.g., counting the poor population), the United States Census Bureau uses a set of annual income levels, the poverty thresholds, slightly different from the federal poverty guidelines. As with the poverty guidelines, they represent a federal government estimate of the point below which a household of a given size has pre-tax cash income insufficient to meet minimal food and other basic needs. There are 48 possible poverty thresholds that a family can be assigned to, which vary based on the family size and the age of its members.