NEW YORK — The crowds of bargain hunters that rush through U.S. store doors the day after the Thanksgiving holiday have thinned out.

U.S. shoppers spent $9.1 billion at stores on Black Friday, according to data out Saturday from research firm ShopperTrak. That’s a drop of 7 percent compared with the same day last year.

But it’s too early to call the holiday shopping season a dud, said Bill Martin, ShopperTrak’ s co-founder. Sales on Thursday, the Thanksgiving holiday, jumped 24 percent to $3.2 billion. And overall sales for the two days are expected to slip half a percent to $12.29 billion. The figures don’t include online transactions.

For the second straight year, the report suggests that more people avoided the crowds on Black Friday by avoiding time at home on Thanksgiving Day. This year, many large retail stores decided to open their doors to eager shoppers for extended hours on the holiday.

“People are changing their behavior,” Martin said. “We’ve seen this for two years in a row now. Stores opening on Thanksgiving are simply eroding sales from Black Friday.”

The popularity of shopping online has also lured people away from brick-and-mortar stores. In a separate report out Saturday, IBM said online sales for Black Friday climbed 9.5 percent over the same day last year. More than one of every four transactions were made using a smartphone or tablet computer.

Some people saw no reason to rush to the stores before the weekend.

In Phoenix, Elaine Vanas and her daughter, Christine, were out picking up coats on Saturday, saying they disliked the long lines on Black Friday. At JC Penney, the two found a $50 house coat for Christine’s grandmother for $20, and bought another $200 coat for $20.

“I’m not cheap but I’m frugal,” Elaine Vanas said.

Retail businesses have highs hopes for the holiday shopping season. The National Retail Federation predicts that sales for the last two months of the year will hit $616.9 billion, an increase of 4.1 percent over the same period of 2013. That would count as the biggest increase for that sales period since 2011, but it would still be slower than the 6 percent pace typical before 2007, the year the Great Recession started.

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