BARRINGTON, Ill. — With Amazon, Wal-Mart and Overstock.com potentially making online grocery shopping and home delivery a threat to convenience stores, a new study has documented demographics and characteristics of this steadily growing consumer trend.

Estimated to be a $25-billion business in the United States today, online shopping–as defined in the newly released 2015 eCommerce SuperStudy from consulting firm Willard Bishop–includes people who order food, beverage or packaged goods online for either home delivery or pickup at a designated location.

“People are using it, ordering consistently; spending goes up over time, [their] comfort level goes up over time, and it’s only going to grow,” said Paul Weitzel, managing partner for the Barrington, Ill.-based firm. “If people don’t have to leave the house [to shop] and start to define that as more convenient, it poses a threat to c-stores.”

The threat is particularly strong for convenience retailers who operate what Weitzel calls “neighborhood stores” vs. “grab-and-go” or “commuter” stores. He told CSP Daily News that c-stores will always play a role for people who are already out of the home going to work or running errands, but for trips that include the emergency beer run or the grocery trip for those c-stores in rural areas, the purposes overlap.

Two groups—millennials and the elderly—also emerged as demographic segments that seem particularly fond of online shopping and home delivery. Millennials are highly tech savvy, while the elderly are less mobile and are in need of the service, Weitzel said.

The study also found the basket makeup to be different for a home delivery versus a pickup. “The soccer mom wanting to drive in and pick up an order while her kids are in the car is going to order something different than a home delivery to someone who’s elderly,” he said.

Other key findings from the study include a list of top-tier consumer packaged goods (CPG) manufacturers that are winning the “fair share” battle for food and non-food sales within the digital marketplace.

“Overall, center-store food and non-food categories are doing very well online; however, the different fulfillment models cause category performance to vary significantly,” Weitzel said. “Campbell’s, ConAgra, Kellogg’s, Kimberly-Clark and Mondelez, represent the top five manufacturers capturing a disproportionate share of online sales.”

The study, which benchmarks category performance and ranks manufacturers across four leading “click-and-mortar retailers,” assesses the value of eCommerce programs, particularly in the areas of financial metrics, category performances and shopper behaviors, Weitzel said.

As an industry consultant, Willard Bishop creates performance-based strategies for both the supply and demand areas of the industry, integrating shopper-based analytics and cost modeling to identify and quantify opportunities.

Watch for the second part of this report on CSPnet.com and CSP Daily News.