In the past, adding coffee to the menu was an easy way to juice sales. A few years ago amid lagging doughnut sales, Krispy Kreme (NASDAQ:DNUT) thought by pushing coffee with its glazed confections could have the beverage grow to 10% of sales. According to the National Coffee Association, 67% of Americans drink at least one cup of coffee in the past day and 75% in the past week. The biggest growth market is by consumers 25 years and older. Also, the 60-and- older crowd had the greatest jump, from 67% having ...