Smartphones’ share of US online retail sales, excluding apps, climbed to 31.8% in Q3 2018, according to a report from Criteo.

That marks a 14% year-over-year (YoY) increase in share, while tablets’ share dropped 12% YoY and laptops’ and desktops’ fell 5% YoY. This demonstrates the growing importance of mobile, and specifically smartphones, to both the present and future of US e-commerce.

While mobile commerce (m-commerce) is on the rise in the US, it already accounts for most sales in several other countries. M-commerce made up 40% of sales in the US in Q3 2018, excluding apps, a notable increase from its 35% share a year prior.

However, it holds a 50% or higher share in nine other countries, with Sweden leading the way at 60%, and m-commerce has a larger share in 18 countries than it does in the US. So, although retailers and brands may be bolstering their mobile capabilities to take advantage of m-commerce’s growing importance in the US, it’s even more important that they invest in the area in other countries, or they’ll disappoint consumers using the popular channel.

Leveraging the smartphone’s omnichannel capabilities can allow retailers to maximize its value. Only 7% of consumers shopped online and in-store for a product, but that small contingent accounted for 27% of sales made in Q3. Retailers need to provide omnichannel tools and experiences to capitalize on this opportunity, and smartphones are the perfect device for doing so.

They’re convenient, can be used in-store, and hold a growing influence on all retail sales, in addition to their rising e-commerce importance. Displaying details like where products are located in-store on mobile sites and apps can encourage and simplify omnichannel shopping, while in-store research tools such as Walmart’s AR comparison feature can offer more information to drive conversion among omnichannel shoppers.

In addition to preparing for the future, investing in m-commerce should pay dividends immediately given its tremendous performance over the holidays. Smartphones brought in $33.3 billion in sales from November 1 through December 19, according to Adobe, and tablets racked up $9.8 billion.

These devices accounted for 40% of retail revenue and 58% of traffic — 50% through smartphones and 8% via tablets. This shows how important it is to invest in m-commerce, as retailers and brands with lackluster mobile experiences risk alienating consumers in an extremely popular channel.