https://ourworldindata.org/data-insights/almost-all-livestock-in-the-united-states-is-factory-farmed
Estimates are still quite high globally too. Around 94% of all globally farmed animals are factory farmed. 74% of all farmed land animals are factory farmed and virtually all farmed fish
The factory farming definition they use is more specific than that. It's based on the numbers per location