A survey conducted Aug. 5-12 by Prosper Insights and Analytics found that on average families with children in grades K-12 indicated they were 52.1 percent done with their school-supply shopping.
Families with college students on average indicated they were 49.5 percent done with back-to-college shopping, the survey found.
The results for 2013 are a record high for the survey for this time of year, the NRF said.
The NRF in a Tuesday release said that by this time of the year in 2012, families indicated on average they were 40.1 percent done with back-to-school shopping.
"Shopping early and often has become a sign of the times as budget-conscious consumers aim to ease the brunt of large spending events," said NRF President and Chief Executive Officer Matthew Shay.
"In the weeks ahead, last minute shoppers can expect promotions to continue through Labor Day as retailers try to make room for fresh fall merchandise," Shay said.
The trade group said it expected back-to-school and college spending to reach $72.5 billion this year.
The NRF said the survey involved 5,679 consumers. The results include a margin of error of plus and minus 1.3 percentage points, the NRF said.
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