Have Americans finally had enough of Black Friday madness?

Sales, both in stores and online, from Thanksgiving through the weekend were estimated to have dropped 11 percent, to $50.9 billion, from $57.4 billion last year, according to preliminary survey results released Sunday by the National Retail Federation. Sales fell despite many stores’ opening earlier than ever on Thanksgiving Day.

And though many retailers offered the same aggressive discounts online as they did in their stores, the web failed to attract more shoppers or spending over the four-day holiday weekend than it did last year, the group said. The average person who shopped over the weekend spent $159.55 at online retailers, down 10.2 percent from last year.

Over all, 133.7 million people shopped or planned to shop at stores or online over the four-day weekend, 5.2 percent fewer than last year, the federation said. And shoppers spent an average of $380.95 over the four days, 6.4 percent less than the $407.02 they spent last year.

Executives at the retail federation, which had predicted strong growth in sales this holiday season, appeared at a loss to fully explain the drop-off.