Google Express, a delivery service for consumer goods sold through Walmart, Target, Costco and other retailers, in the Shopping auction continues to account for more ad impressions than in the past, according to data released Monday.

Merkle attributes the increase to Shopping Actions, which Google announced in March. The service aggregates products from a variety of retailers without the consumer having to go to individual retail websites to make a purchase. The ads for these products are sometimes placed alongside traditional Google Shopping ads in the product ad carousel.

Andy Taylor, associate director of research at agency Merkle, writes that analysis conducted in early May shows the presence in Google Shopping ad auctions grew meaningful during the 2017 holiday season, but there wasn’t a clear increase in impression share until Google introduced Actions.

Merkle, in the report titled Dossier 9.1, describes the difference between Shopping Actions and Purchases on Google as the former being priced based on a pay-per-sale model, while the latter followed Google’s traditional pay-per-click model. Brands must complete a Shopping Actions interest form and, if determined to be eligible, will be contacted by Google to learn more about next steps.

Beginning a few weeks ago, Taylor began to see Google Express impression share surge. “Looking at a set of about a dozen advertisers that have regularly seen Google Express in Auction Insights reports at values greater than 10% (since less than 10% values are shown as ‘<10%’) since early May, we find that Google Express’s average impression share increased from 14% the week of 5/7 to 23% during the final week in July,” he wrote.

Google Express became one of the top ten biggest competitors in terms of Shopping impression share for all brands by the end of July, wrote Taylor. Now the offering continues to expand across all three types of devices, desktop, smartphone and tablet.

The advertisers in the analysis sell a range of products like furniture, general home goods, novelty gifts, and electronics. Every member in the sample analysis experienced higher impression share from Google Express during the last week shown in the charts than the first.