Even though St. Patrick's day is known as a drinking holiday, it doesn't do too much to spur beer sales for home consumption. Nielsen, a market research company, tracks the purchase of beer for the two weeks leading up to holidays... and St. Patrick's is the lowest. Of course, St. Patrick's day also sees a higher number of people going out to restaurants and bars (only 16.7% went to a private St. Patrick's party in 2009).