A new poll shows Brazilian President Dilma Rousseff's popularity has plummeted since the outbreak of nationwide protests several weeks ago.

The Datafolha survey published Saturday finds 30 percent of respondents giving positive marks to Rousseff's government, down from 57 percent registered in its previous poll before the demonstrations began.

Datafolha says it's the biggest drop in a president's approval rating since a 1990 fall for then-President Fernando Collor de Mello, who was forced from office because of a corruption scandal.

The recent protests first targeted transportation fare hikes and quickly expanded to a variety of causes including government corruption, high taxes, poor public services and billions of dollars spent for next year's World Cup soccer tournament.

Datafolha surveyed 4,717 people on June 27 and 28. Its poll has a margin of error of 2 percentage points.