Virtual reality continues to grow, and Steam is seeing more users with VR headsets hooked up with each passing month. An analysis by Road to VR indicates that in December, a record number of Steam users had VR headsets connected – about 1.3 million, if their math is correct.

As it turns out, determining exactly how many Steam users have VR headsets connected to their computers is trickier than it might seem. Valve runs a monthly Steam Hardware Survey to create a snapshot of users’ hardware, so you might think the information is right there. But that’s not quite the case: first, Valve’s survey only collects data from a statistically significant sample of Steam users, and second, the figures it provides to the public only express VR users as a percentage of Steam’s total user population – a figure that is constantly changing. So while the percentage of Steam users who have VR headsets might look static, the actual number of those users could be growing.

Road to VR has developed its own model to estimate the total number of ‘monthly connected headsets’ – that is, the raw number of powered on, unique headsets connected to Steam users’ PCs during any given month. Road to VR’s model corrects for the changing number of Steam users to work out what that percentage figure means, and the estimate it comes up with for December is a record-breaking 1,342,000 VR headsets.

Road to VR notes that there are a few factors that aren’t accounted for in the monthly connected headsets figure. It doesn’t tell us, for instance, how often those headsets are being used, nor does it provide any insight into non-Steam marketplaces like Oculus PC.

But it does show us a bit about how the VR market is growing on Steam. December’s figure beat the previous record of 1.2 million set in September, and it’s up 75% over the year prior. Road to VR makes a tentative guess that, based on current trends, the total number of monthly connected VR headsets on Steam could increase to 2.75 million by December this year.

However, any number of factors could impact this figure. The VR-only Half-Life: Alyx comes out in March and could drive additional sales, but cost-of-entry prices that remain relatively high could be creating a hard ceiling on growth.

One thing is clear though: don’t count VR out yet – it’s likely to be a significant year for the format. To get prepared, check out our list of the best VR games on PC.