US retailers hope hordes of bargain-hunters can lift the economic gloom as the holiday shopping season begins. After polishing off Thanksgiving turkeys, millions of Americans will head to the shops on Friday for the busiest shopping day of the year.Black Friday - so-called as it is when many retailers head out of the red and into the black - sees many stores open at midnight, or even earlier this year.Half of the entire US population is expected to hit the shops this weekend.The National Retail Federation (NRF) said 152 million people would visit stores in search of bargains this weekend, up 10% from last year.Consumer spending accounts for about 70% of US economic activity. Economists and business executives will be watching the 2011 retail bonanza closely.For the past six years, a combination of increasingly early opening times and an array of discounts have helped make the day after Thanksgiving the biggest shopping day.Between 25-40% of annual US retail sales take place during November and December.Analysts say a powerful start to the shopping season could stimulate more hiring of staff by the retail industry, which supports about one-quarter of all jobs in the US.Retail hiring for the season has still not yet rebounded to its 2005 pre-recession peak of 642,000 workers, according to the NRF. \"A bad holiday season would raise recession fears again, whereas a strong one would start to dispel those fears,\" said Scott Hoyt, of Moody\'s Analytics.lack Friday usually sees shopping chains thrown open their doors in the early hours. But this year that rush has crept into Thanksgiving Day itself.Wal-Mart, which opens many of its \"super-centres\" 24 hours a day, will also open the rest of its stores at 22:00 on Thanksgiving. About 1,000 Gap stores will be open on Thanksgiving and several large retailers, including Target, Best Buy and Macy\'s, will open at midnight.On Thursday, US President Barack Obama officially proclaimed the holiday, which celebrates the Pilgrims\' first harvest in what is now the state of Massachusetts.An estimated 43 million Americans are expected to travel by road and air before and after Thanksgiving, the highest number since 2007.Meanwhile, the annual Thanksgiving parade made its way on Thursday through the crowded streets of a sunny New York. About 3.5 million people were expected to join the route, with an estimated 50 million watching from home. which began in 1924 - this year featured more than 40 giant helium balloons, 27 floats, 800 clowns and 1,600 cheerleaders.Elsewhere in New York, Occupy Wall Street protesters were marking the holiday with an \"open feast\" of 3,000 individually wrapped plates of food at Zuccotti Park, organisers said.