Brazil’s president has come under more public pressure to quit, with protest rallies in 156 cities over the weekend. Although well over half a million people turned out, compared with two million who demonstrated against Dilma Rousseff on March 15th, polls show dissatisfaction reaching new depths: 75% want Congress to launch impeachment proceedings.

Rousseff was only sworn in a few months ago, winning a second term in office in elections last October, but since then her popularity rating has crashed, to a reported 13%.

This is largely owing to the state oil company Petrobras corruption megascandal. Brazilians hold Rousseff responsible for not stopping embezzlement from 2003-2010 when she was chairwoman of the board. More than 50 politicians, including members of Rousseff’s Workers’ Party (PT), are under investigation.

Rousseff signed anti-corruption measures last month but it hasn’t calmed a furious public, as Brazil’s economy continues to tank.

Economist Gilberto Braga said: