Between 2013 and 2035, this investment would avert an estimated 147 million child deaths, 32 million stillborn deaths and 5 million maternal deaths. Yet more than 100 developing countries lack the civil registration and vital statistics (CRVS) systems needed to generate accurate birth and death data. That figure includes 39 per cent of children in sub-Saharan Africa and 44 per cent of children in South Asia. In the absence of reliable data, estimates for child mortality in countries lacking CRVS systems are based on a sophisticated statistical model using survey responses, census information and other sources.