SOFIA, July 11 (Reuters) - Bulgaria"s centrе-right GERB party of former Prime Minister Boyko Borissov was seen winning Sunday"s national election with around 22-23% of the vote, exit polls by Gallup International and Alpha Research showed. Alpha Research estimated GERB"s share at 23.5%. Gallup International found it had won 22.1%. The new anti-establishment There Is Such a State (ITN) party was a very close second with 21.5-22.3% in the election, which was the second to be held in three months. GERB has dominated Bulgarian politics over the past decade. It was seen as falling short of winning a majority and was unlikely to be able to form a ruling coalition to replace the interim administration that was appointed after the inconclusive election in April.