It depends on how they computed average life expectancy. Due to high infant mortality, life expectancy of survivors can be in fact much higher.<p><i>"Life expectancy is heavily dependent on the criteria used to select the group. For example, in countries with high infant mortality rates, the life expectancy at birth is highly sensitive to the rate of death in the first few years of life. In these cases, another measure such as life expectancy at age 5 (e5) can be used to exclude the effects of infant mortality to provide a simple measure of overall mortality rates other than in early childhood.</i>"<p><a href="http://en.wikipedia.org/wiki/Life_expectancy" rel="nofollow">http://en.wikipedia.org/wiki/Life_expectancy</a>