WASHINGTON--(BUSINESS WIRE)--Summer is in full swing and Americans are ready to put on their red, white and blue to celebrate Independence Day with friends and family — and plenty of food. According to the National Retail Federation’s 2015 Independence Day Survey conducted by Prosper Insights & Analytics, more than 156 million consumers—nearly two thirds of those celebrating (64.4 percent), are planning to take part in the patriotic holiday by attending a cookout, picnic or barbecue, spendi