St. Patrick's Day is coming up in a couple weeks and the already fast-growing Irish whiskey category will be center stage. For the 12 weeks ending February 2 Irish whiskey sales were up 22%, with a 19% increase in volumes, per Nielsen data. The category only represents 1% of sales, but it continues to grab share. For the 12 weeks it took 22 dollar share points, second only to the bourbon category.