https://www.techradar.com/news/oculus-rift-passes-htc-vive-in-the-steam-hardware-survey-for-the-first-time

Step aside, HTC Vive. Oculus Rift has just passed you in the Steam Hardware & Software Survey for the first time ever. 

Here's how it breaks down: Oculus Rift counted for 47.31% of virtual reality headset usage on Steam in February 2018, while HTC Vive came in at 45.38%.