In New York City, hummus joints are scattering about like lettuce from a felafel. But the popularity of the spread made of chickpeas is growing, especially at retail. Last year, the refrigerated spreads category had double-digit unit growth, with volume sales up 10.4% over the 52 weeks ending Dec. 2, according to Chicago-based SymphonyIRI. This growth comes after a unit sales increase of 10.8% in the 52 weeks ending Jan. 1, 2012. From 2009 to September 2012, the most popular flavors of hummus were plain (61%), roasted (18%), garlic (11%) and red pepper (10%), according to a recent Mintel report.