The National Retail Federation expects Americans to spend $5.9 billion on St. Patrick's Day celebrations this year, according to new survey results published by the federation last week. That would represent an increase from last year's total spending of $5.3 billion. Consumers are expected to spend an average of $39.65 per person, up from last year’s previous record of $37.92. The holiday is most popular among those ages 18-24, with 77 percent of them saying they plan to celebrate.