disproportion
noun/ˌdɪsprəˈpɔrʃn/ 
[uncountable, countable] (formal)the state of two things not being at an equally high or low level; an example of this
disproportion (between A and B)the disproportion between the extra responsibilities and the small salary increase disproportion (of A to B)a profession with a high disproportion of male to female employees