It all narrows to water, sanitation and maternal health care, streamline that, and life expectancy will go up.
If you have a child who dies at 1yr old and a citizen at 80 yrs old, the life expectancy there is 40 yrs. Infant mortality rate is the litmus test of how a country is developed, you don't need any othe data, just focus on that and life expectancy will go up.
The Nairobi Governor who will go down in History as the Greatest will be one who will nailed it on sanitation, clean water and maternal health care.