Despite many retailers’ plans to open earlier on Thanksgiving Day, fewer consumers say they expect to shop during the holiday this year than last, possibly an indication that improved economic conditions means that people are less desperate for the deepest discounts. Of the 140 million people who said they may or will shop online or in stores during Thanksgiving weekend, 25.6 million, or 18.3 percent, said they plan to shop Thursday, down from 23.5 percent who planned to do so last year, according to a survey released this week by the National Retail Federation. Nearly 80 percent of Millennials, loosely defined as people born in the 1980s and ’90s, plan to shop during the Thanksgiving weekend, more than any other age group, though fewer plan to venture out on the holiday this year than last and more plan to shop on Black Friday, the day after Thanksgiving that traditionally starts the holiday shopping season. Black Friday remains the most popular shopping day of the holiday weekend, drawing 68.2 percent of anticipated shoppers, or 95.5 million people, followed by Saturday, Sunday and Thursday. Many major retailers have announced plans to open earlier on Thanksgiving Day, with Macy’s, Target, Sears, Kohl’s, Staples and others opening at 6 p.m., while J.C.