Consumer confidence in the metropolitan region is at its highest level in 9 1/2 years because of sustained low gasoline prices compared with past years, according to a recent survey.

The Siena College Research Institute said Thursday that its Index of Consumer Sentiment was 91.1 points last month for Long Island, New York City and its northern suburbs, as the cost of gasoline was less than in recent years.

The index was 93.3 in February 2007, months before the region and country fell into recession.

The index climbed to 90.7 points in March, which was also a nearly nine-year high, and then dipped to 90.2 in June.

Index readings above 76 points indicate the number of residents who are optimistic about their immediate financial future is larger than the number who are pessimistic.

In September 2015, the metro area’s confidence index was 87.1. Siena has conducted surveys four times a year since 2014; previously, they were done monthly.

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Siena pollster Douglas Lonnstrom said, “As gas prices held steady, concern about the effect on the family budget dropped . . . However, the good news was partially offset by worries about food prices.”

He noted the number of metro area residents who said the cost of gasoline was either a serious or very serious problem last month was 29 percent, down from 30 percent in June.

Concern about food prices was up slightly, 65 percent last month compared with 61 percent in June.

Economists and retailers closely follow confidence indexes because they can indicate whether shoppers are willing to open their wallets. Consumer spending represents about 70 percent of economic activity in the metropolitan area and nationwide.

Siena polled 800 residents statewide between Sept. 1 and 30; the margin of error was 4.2 percentage points. The survey has been conducted for more than 15 years.