Tractica continues to forecast strong growth for the wearables market. In a new report, the market research firm predicts a CAGR of 36.9 percent between 2015 and 2021.

In a statement, the firm asserts that while the wearables market “experienced ups and downs” last year, its unit shipments were higher than expected, at about 85 million; and that number is predicted to reach 559.6 million by 2021. According to research director Aditya Kaul, last year’s growth was led by fitness trackers, which wound up “outperforming industry expectations”, while the year saw “smart watches coming out strong.”

Despite Kaul’s assertion that fitness tracking devices continue to be “the overwhelming driver for wearables”, that last point should offer some validation to the likes of the Apple Watch, given that analysts have been divided over its relative success in the market. Meanwhile, Kaul says there are “a number of micro-segments emerging,” including smart footwear and smartwatches for kids, that will continue to “drive this market forward.”

The report displays continued enthusiasm for the market on the part of Tractica, which started its own market advisory service last year in anticipation of a market boom. Meanwhile, other market research firms have, to varying degrees, shared Tractica’s view that growth is in the cards.