Using @sportsdataverse it is estimated that there have be 2377 on-side kicks in cfb games between 2003 and 2021.

Of those 2377, 2133 came in a situation in which the kicking team was tied or trailing the receiving team. Leaving 244 cases where the kicking team was leading.

— Erik Hall 🏴‍☠️ (@DjDataScience) August 28, 2022