Google Transparency Report on YouTube Community Guidelines enforcement
Total videos removed: 9,790,082 in Jan to Mar 2018
At YouTube, we work hard to maintain a safe and vibrant community. We have Community Guidelines that set the rules of the road for what we don’t allow on YouTube. For example, we do not allow pornography, incitement to violence, harassment, or hate speech. We rely on a combination of people and technology to flag inappropriate content and enforce these guidelines. This report provides data on the flags YouTube receives and how we enforce our policies.
https://transparencyreport.google.com/youtube-policy/overview