Kenyan children walk back home from school in Kibera, Nairobi, Kenya, May 30, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Zhang Weiyi)

A boy picks up fish at Zanzibar, Tanzania, March 30, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Qi Lin)

A 15-year-old girl works as a porter in a stone career in Antananarivo, capital of Madagascar, April 26, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Mika Rajaonarison)

Children raise their hands on a class in Nairobi, Kenya, April 11, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Meng Chenguang)

Somali girls take an examination in Mogadishu, Somalia, May 11, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Qi Lin)

Children play in the street at Zanzibar, Tanzania, March 30, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Qi Lin)

Students rest at St. Juliet Primary School in Kibera, Nairobi, Kenya, May 30, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Zhang Weiyi)

A Kenyan boy rolls a tire at parkland, Nairobi, Kenya, Feb 26, 2013. According to the Millennium Development Goals Report 2012 released by the United Nations, the living conditions of Sub-Saharan African children have been improved, as the enrolment rates of children of the primary school age increased markedly from 58 to 76 percent and the under-five mortality dropped by 2.4 percent a year during 2000-2010. (Xinhua/Qi Lin)