Worldwide spending on the Internet of Things is expected to grow 16.7 percent year-over-year in 2017, reaching just over $800 billion, according to a new report from from IDC.

By 2021, global IoT spending is expected to total nearly $1.4 trillion as organizations continue to invest in the hardware, software, services, and connectivity that enable the IoT, according to a press release about the report.

"The discussion about IoT has shifted away from the number of devices connected," Carrie MacGillivray, vice president IoT and mobility at IDC, said in a statement. "The true value of IoT is being realized when the software and services come together to enable the capture, interpretation, and action on data produced by IoT endpoints."

The IoT use cases that are expected to attract the largest investments in 2017 include manufacturing operations ($105 billion), freight monitoring ($50 billion), and production asset management ($45 billion).

Smart grid technologies for electricity, gas and water and smart building technologies are also forecast to see significant investments this year ($56 billion and $40 billion, respectively). While these use cases will remain the largest areas of IoT spending in 2021, smart home technologies are forecast to experience strong growth (19.8 percent CAGR) over the five-year forecast. The use cases that will see the fastest spending growth are airport facilities automation (33.4 percent CAGR), electric vehicle charging (21.1 percent CAGR), and in-store contextual marketing (20.2 percent CAGR).