Brazilian President Dilma Rousseff reacts during a Summit of Heads of State of MERCOSUR and Associated States and Meeting of the Common Market Council in Brasilia in this July 17, 2015 file photo Thomson Reuters Dilma Rousseff is now Brazil's most unpopular democratically elected president since a military dictatorship ended in 1985, says a poll out Thursday that put her approval rating at eight percent.

Seventy-one percent of those questioned in the Datafolha survey said they disapprove of the way Rousseff is doing her job, up six points since June. Her approval rating is down from 10 percent.

And two-thirds would like to see her impeached.

Rousseff, the successor of wildly popular former president Luiz Inacio Lula da Silva, faces widespread anger over corruption, a stagnant economy and growing unemployment.

Her numbers are worse than those of Fernando Collor de Mello, who resigned in 1992 over corruption allegations. Right before he stepped down he had an approval rating of nine percent and disapproval of 68 percent.

"Dilma has thus become the president with the worst approval rating among all those elected directly since the return of democracy," said the web site of the newspaper Folha de Sao Paulo, which belongs to the same group as Datafolha.

Datafolha began conducting national polls during the rule of Collor. In 1990 he became the first democratically elected president since the end of the military regime.

His predecessor, Jose Sarney, took power in 1985 as vice president under Tancredo Neves. Neves had been elected president by congress after 21 years of military rule, but died before he could assume office.

Rousseff began her second term in January after winning re-election by a thin margin, and things are already looking grim.

Rousseff waves during a meeting with governors at Alvorada Palace in Brasilia Thomson Reuters She is under siege from a corruption scandal at the state-run oil giant Petrobras that has also implicated the ruling Workers' Party.

She chaired the board at the company, from 2003 to 2010, a period during which the corruption allegedly flourished. She has not been personally implicated in the scandal.

Once a much hailed success story, Brazil's economy is now sputtering and inflation is high.

A rally calling for her resignation is scheduled for August 16.

The new poll shows that 66 percent of those questioned would like to see Congress open impeachment proceedings against Rousseff.

The government's disapproval and popularity numbers do not vary much by people's income or education level, which shows that even among low-earning Brazilians -- traditionally a bastion of support for the Workers' Party -- frustration is growing.

The poll was conducted this week among 3,358 people and had a margin of error of two percentage points.