Internet of Things (IoT) cellular connections are on the rise as operators devote more resources to building their IoT businesses. According to a research note from Goldman Sachs, IoT connections jumped 33 percent year-over-year in the second quarter.

The investment firm cautions, however, that while cellular connections are on the rise, they still represent a small portion of total IoT end points. The majority of IoT connections are handled by short-range wireless connections like WiFi, Bluetooth, or ZigBee.

Nevertheless, the growth in cellular IoT connections does show the pace of IoT adoption and the growing commitment operators are making to securing IoT customers.

AT&T, an early proponent of IoT, reported that it added 1.2 million devices in the second quarter, which was down 17 percent from the previous year. However, the company has more than 29 million devices connected to its network, 8 million of which are automobiles.

Vodafone reported more than 41 million IoT connections in the second quarter, an increase of 39 percent. The company said its IoT revenues were $174 million in the second quarter.

Verizon didn’t break out its IoT connections from its wholesale connections in the second quarter, however the company did say its IoT revenue was $205 million in second quarter, a year-over-year increase of about 25 percent.

Verizon recently announced plans to purchase fleet management software firm Fleetmatics for $2.4 billion in cash as a way to strengthen its IoT portfolio. A large incentive for the deal was the acquisition of Fleetmatics’ 37,000 customers and its 737,000 subscribers.

Meanwhile, Ericsson earlier this summer released a report that predicted that by 2018, IoT connections will surpass smartphone connections. And the vendor also predicted that by 2021 there will be 28 billion connected devices, 16 billion of which will be IoT-related. In North America alone, Ericsson predicts there will be about 3 billion IoT connected devices by 2021.