Almost two thirds of Brazilians favour the impeachment of President Dilma Rousseff over a corruption scandal at state-run oil company Petrobras, but roughly as many doubt it would drive her from office, according to a poll released on Saturday. The survey by polling firm Datafolha showed 63 percent of respondents support impeachment in light of the widening police investigation into a huge kickback scheme at Petroleo Brasileiro SA, as the oil giant is formally known.