Sentence:  Determine the ratio of 50 % to the average per capita income of the <WSD>U.</WSD> S. ( Divide 50 by the result obtained in item 2 above . ) 
Meaning of the word marked with <WSD> tags:  North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776