A statistics question?

A study is carried out to determine the effect of party affiliation on voting behavior in a certain city. the city is divided up into wards. in each ward, the percentage of registered democrats who vote is higher than the percentage of registered republicans who vote. true or false: for the city as a whole, the percentage of registered democrats who vote must be higher than the percentage of registered republicans who vote. if true, why? if false, give an example.