Online sales of consumer packaged goods (CPGs) rose 35.4% in 2018, according to a report from research, data and predictive analytics firm Information Resources Inc. (IRI).

CPGs are items used daily by most consumers and need to be replaced frequently, such as packaged foods, beverages, toiletries, over-the-counter drugs and other consumables.

Based on data from IRI’s E-Market Insights online sales measurement and insights service, online CPG sales in the United States totaled $58.6 billion last year, accounting for 11% of total CPG retail sales. Online sales also represented 64% of the growth in total (online and offline) U.S. CPG sales in 2018.

E-Market Insights collects data from 12 million online shoppers along with point-of-sale data from partners including retailers and third-party companies.

The report says more than half of online CPG purchases are from “pure-play” online retailers—such as online grocers Peapod (a unit of Ahold Delhaize, No. 62  in the Internet Retailer Top 1000) and FreshDirect LLC (No. 81). Online CPG sales at bricks-and-mortar multi-category and specialty retailers accounted for just 23% of the total.

Competing in the ecommerce CPG market could be a challenge for smaller retailers with fewer resources, says Joan Driggs, vice president of content and thought leadership for IRI. But she also sees it as an opportunity.

Retailers, for example, can build loyalty by focusing on finding ways to offer excellent customer service and being extremely responsive to local consumers. Capitalizing on ecommerce will require grocery retailers to think through how omnichannel services can be used to complement their strengths and make it easier for customers to shop with them, she says. But there is no one right answer.

“It’s up to the retailer to decide what the sweet spot is to them, depending on their size and resources,” Driggs says.

Non-food items, particularly personal care and home care products, are the top-selling CPGs online. IRI says vitamins, pet food and supplies, and skin care products are the most popular. That makes sense, the report says, because pet food and supplies are often bulky, while vitamins are likely seen as easier to shop for online than in a store—because online shopping provides keyword search functionality and easy access to additional information.

Shoppers also are increasingly going online for more sensitive purchases. Among the items with the fastest-growing online sales are gastrointestinal liquids, up 310% year-over-year and adult incontinence products, up 84%.

In addition to the E-Market Insights data, the IRI report includes the results of a survey of 2,164 consumers conducted Dec. 7-14, 2018. The goal of the survey, which IRI conducts quarterly, is to track consumers’ financial confidence and how that affects the ways they buy and use CPG products.

Among the omnichannel services likely to drive customers to buy CPGs online, online purchasing with free delivery was the most popular, cited by 57%. That was followed by online purchasing with fast delivery (47%) and online purchasing with in-store pickup (40%). In each case, the popularity of the omnichannel service was more popular among millennials (ages 18 to 34) and Gen X respondents (ages 35 to 44) than with older survey participants.

Consumers are beginning to bring some of their offline habits to online CPG shopping, Driggs says. That includes trying to save money. 54% of survey respondents plan to download coupons from a retailer or manufacturer website in the coming year, and 53% plan to compare prices on area retailers’ websites to find the lowest prices on needed items. 23% of respondents plan to order CPG items online and pick them up in a store, and 22% plan to order such goods for home delivery. Less popular were subscription services for grocery items (cited by 11% of respondents) and online meal-kit delivery services (5%).

Even when consumers do not buy CPG items online, their interactions online can influence their buying decisions. According to the IRI survey, 46% of respondents said they would switch to a new brand if they read a food review online. That number was significantly higher among millennial (56%) and Gen X (58%) participants.