There’s no denying the popularity of pizza, especially when it’s National Pizza Month in the US. And when you consider the size of this $40 billion pie, that’s a ton of slices. In fact, Americans consume 350 slices per second.

Ninety-three percent of Americans eat at least one pizza a month, and they’re consuming a large portion of them in the comfort of their own homes. Notably, the popularity of America’s No. 1 meal choice translates into about $3 billion in annual sales for grocery retailers, whose offerings are split between the in-store deli and frozen foods departments.

At the grocery store, pizza dynamics are changing as the effects of the recent recession dissipate. For example, when economic conditions are tight, some consumers would likely opt for frozen over deli pizza as a means of feeding a craving for pizza while being cost conscious. Since the recession, however, sales dynamics have shifted, spurring growth in the deli department and declines in the frozen aisles. Frozen pizza, however, has a much higher penetration rate than deli pizza does (55% vs. 15%).

With an average price of $6.37, grocery deli pizza became a more affordable alternative to pizzerias during the recession. During the recession, deli pizza sales reflected consumer attitudes toward discretionary spending. When consumer confidence hit its low in 2011, sales of deli pizza sales skyrocketed. Despite a frugal mentality during the recession, pizza buyers were still willing to spend more for deli-prepared pizza than frozen pies. Deli pizza maintained a 30 percent price premium over frozen pizza and consistently gained sales over the past three years, while sales of frozen pizza declined.

Now in a recovering economy, deli pizza sales are still rising while frozen pizza sales continue to decline. Sales aren’t growing for all types of deli pizza, however. Shrinking household sizes are affecting growth of small sizes in deli pizza. Whole pizzas account for over 50 percent of deli pizza sales, but whole pizza sales declined 4 percent over the past three years. Deli pizza slices and calzones/Stromboli—both viable options as dinner for one—saw improved sales during the same time. Moreover, deli pizza sales are strong across all household sizes—from start-up families to senior singles and couples—whereas frozen pizza sales are strongest among households with children.

As with any category, consumers have steadfast preferences when it comes to their take-home pizza. Most pizza buyers have a discernible preference for deli or frozen, as less than one-fifth (18%) buy both types in a given year. While frozen and deli pizzas aren’t really competing for the same consumer, they are meeting the same buyer needs.

By taking a look into the shopping baskets of both buyers, we can gain insight into certain consumer behaviors. And not surprisingly, buyers of frozen and deli pizzas are both in the market for time-saving grocery items, including shelf-stable prepared foods, frozen snacks and prepared seafood. For frozen pizza buyers, however, we can see the time-saving theme exemplified to some degree, as their baskets often also include frozen dinners, frozen breakfasts and packaged macaroni and cheese.

In looking at what’s driven the growth in deli pizza sales in recent years, we can apply many of the lessons learned to the freezer aisle. It is, however, important to realize that deli and frozen pizza buyers have very little overlap, so implementing the successful characteristics of deli pizza to frozen pizza (and vice versa) may help spur sales spikes from loyal frozen shoppers while possibly sparking interest and crossover sales from deli pizza buyers in the process.