Leader of centre-right GERB party Boiko Borisov (C) waves to supporters as he leaves a polling station after casting his vote in Sofia May 12, 2013. Bulgarians voted on Sunday in an election marred by suspicions of rigging, with expectations of a close result that is likely to prolong uncertainty in the European Union's poorest country. REUTERS/Stoyan Nenov (BULGARIA - Tags: POLITICS ELECTIONS)