Seems to be 2017? <a href="https://www.semanticscholar.org/paper/Revisiting-the-Netflix-Prize-the-Decade-After-%3A-Cheung-Huang/72b17492e864205979bbf41b32a0ec69f20bf5b7" rel="nofollow">https://www.semanticscholar.org/paper/Revisiting-the-Netflix...</a>