There's nuance to these numbers since interception will be an artifact of where people are looking but 95% of intercepted fentanyl was from US citizens crossing the border.[0]

Funnily enough the Republicans seemed content to sit on their hands and play politics with this so called crisis until the media broke the story.[also 0]

[0]: https://www.nbcnews.com/politics/national-security/border-fe...