study, Desai et al. focussed on education attainments of children and young adults aged 6–29, from lowest caste and tribal populations of India. They completed a national survey of over 100,000 households for each of the four survey years between 1983 and 2000. They found a significant increase in lower caste children in their odds of completing primary school. The number of Dalit children who completed either middle-, high- or college-level education increased three times faster than the national average, and the total number were statistically same for both lower and upper castes. However, the same study found that in 2000, the percentage of Dalit males never enrolled in a school was still more than twice the percentage of upper caste males never enrolled in schools. Moreover, only 1.67% of Dalit females were college graduates compared to 9.09% of upper caste females. The number of Dalit girls in India who attended school doubled in the same period, but was still lower than the national average. Other poor caste groups as well as ethnic groups such as Muslims in India have also made improvements over the 16-year period, but their improvement lagged behind that of Dalits and adivasis. The net percentage school attainment for Dalits and Muslims were statistically the same in 1999. A 2007 nationwide survey of India by the World Bank found that over 80 percent of children of historically discriminated castes were attending schools. The fastest increase in school attendance by Dalit community children occurred during the recent periods of India's economic growth. A study by Darshan Singh presents data on health and other indicators of socio-economic change in India's historically discriminated castes. He claims: In 2001, the literacy rates in India's lowest castes was 55 percent, compared to a national average of 63 percent. The childhood vaccination levels in India's lowest castes was 40 percent in 2001, compared to a national average of 44 percent. Access to drinking water within household or near the household in India's lowest castes was 80 percent in 2001, compared to a national average of 83 percent. The poverty level in India's lowest castes dropped from 49 percent to 39 percent between 1995 and 2005, compared to a national average change from 35 to 27 percent. The life expectancy of various caste groups in modern India has been raised; but the International Institute for Population Sciences report suggests that poverty, not caste,