COLUMBIA, S.C. (AP) - An analysis by The Associated Press shows election lines drawn by South Carolina Republicans after the 2010 Census may have slightly benefited the already dominating party.

The AP scrutinized the outcomes of all 435 U.S. House races and 4,700 state House and Assembly elections last year using a new statistical method of calculating partisan advantage. It's designed to detect cases in which one party may have won, widened or retained its grip on power through political gerrymandering.

According to the "efficiency gap" formula, gerrymandering gave Republicans one excess seat in South Carolina's 170-member Legislature and one extra seat among the state's seven congressmen.

Republicans control both legislative chambers and hold all statewide offices. South Carolina's lone Democrat in Congress represents a district gerrymandered as majority minority.