Rising shopping mall vacancies across the U.S. are driving down rents, signaling that many retail centers continue to struggle despite the country's strong economic growth and buoyant consumer confidence.

The average rent for malls in the third quarter fell 0.3% to $43.25 a square foot in the third quarter, down from $43.36 in the second quarter, according to data from real-estate research firm Reis Inc. The last time rents slid on a quarter-over-quarter basis was in 2011.

Vacancy rates for malls also continued to climb, rising to 9.1% in the third quarter from 8.6% in the second quarter. That is the highest the vacancy rate has been since the third quarter of 2011, when it hit 9.4%, according to Reis.

"The retail sector is still correcting," said Barbara Denham, senior economist with Reis.

This soft spot stands in contrast to much of the rest of the U.S. economy, where robust job growth and a solid economic outlook has boosted consumer and business sentiment. Consumer confidence hit an 18-year high last month, the Dow Jones Industrial Average set another record on Tuesday and a new trade deal with Canada and Mexico has buoyed business sentiment.

Some retailers such as Target Corp. and Nike Inc. have benefited from rising consumer confidence this year and posted strong earnings growth. Their share prices have risen by nearly a third in the year to date.