The business of robotic toys is booming for Amazon. Sales in the category increased by 40% last year, according to research from eCommerce analytics firm One Click Retail.

Amazon captured 16% of the total US domestic consumer electronics market last year, which is worth an estimated US$74 billion. Amazon’s total sales in the robotic toys category—which spans vehicles, learning and explorations, boys role play and drones—were in excess of US$25 million in 2016. And the growth led robotic playthings to climb into the top 25 toy categories on Amazon.com last year.

Earlier this year, Amazon released its annual summer toy list and predicted STEM toys, like the Ozobot from L.A.-based adaptive robotics company Evollve (pictured), would top summer toy sales. And despite lackluster total retail sales in consumer electronics (down 3%) and video games (up 1%), according to One Click Retail, Amazon saw 11% and 20% year-over-year growth rates in these categories, respectively, last year.

Overall in the US, Amazon’s consumer electronics sales rose 20% to US$12 billion. The online retailer has also experienced growth in consumer electronics globally, with annual increases of 15% to US$1.71 billion in Germany in 2016. In Q1 2017, meanwhile, Amazon’s consumer electronics sales saw an increase of 15% in the UK to a record-breaking US$439 million.

Additionally, Amazon saw success last year in its video games category, due in large part to bundled offerings. Four of the top six bestselling items were bundles, helping the online retailer grow to own nearly 7% of the market valued at more than US$30 billion.

One Click Retail reports that PlayStation 4 sold more than US$320 million last year in hardware, consoles and accessories on Amazon, while Xbox One sales of hardware and consoles topped US$185 million. Sony and Microsoft also saw success on Amazon through bundling options, according to the analytics firm.

One Click Retail estimates weekly online sales figures at the SKU level on Amazon using a combination of website indexing, machine learning and proprietary software.