...average 58-year life expectancy of Native Americans in South Dakota... The second group, "America Two," indicates that income isn't the key to a longer life span. This group is made up of 3.6 million low-income whites living in Minnesota, the Dakotas, Iowa, Montana and Nebraska, with an average life expectancy of 79. "White populations living below the median incomes in northern states have the best level of health among whites. That runs counter to everything we know," Murray says.