Street children are poor or homeless children who live on the streets of a city, town, or village. Homeless youth are often called street kids, or urchins; the definition of street children is contested, but many practitioners and policymakers use UNICEF's concept of boys and girls, aged under 18 years, for whom "the street" (including unoccupied dwellings and wasteland) has become home and/or their source of livelihood, and who are inadequately protected or supervised. Street girls are sometimes called gamines, a term that is also used for Colombian street children of either sex. Some street children, notably in more developed nations, are part of a subcategory called thrown-away children, consisting of children who have been forced to leave home. Thrown-away children are more likely to come from single-parent homes. Street children are often subject to abuse, neglect, exploitation, or, in extreme cases, murder by "clean-up squads" that have been hired by local businesses or police. Statistics and distribution Street children can be found in a large majority of the world's famous cities, with the phenomenon more prevalent in densely populated urban hubs of developing or economically unstable regions, such as countries in Africa, South America, Eastern Europe, and Southeast Asia. According to a report from 1988 of the Consortium for Street Children, a United Kingdom-based consortium of related non-governmental organizations (NGOs), UNICEF estimated that 100 million children were growing up on urban streets around the world. Fourteen years later, in 2002 UNICEF similarly reported, "The latest estimates put the numbers of these children as high as one hundred million". More recently the organization added, "The exact number of street children is impossible to quantify, but the figure almost certainly runs into tens of millions across the world. It is likely that the numbers are increasing." In an attempt to form a more reliable estimate, a statistical model based on the number of street children and relevant social indicators for 184 countries was developed; according to this model, there are 10 to 15 million street children in the world. Although it produced a statistically reliable estimate of the number of street children, the model is highly dependent on the definition of “street children,” national estimates, and data collected on the development level of the country, and it is thus limited in range. The one hundred million figure is still commonly cited for street children, but is not based on currently available