how rare is factory AC?

[s10mk]

Hey everyone,
I'm starting to search for my first 67-72 chevy, I would like to fix one up into a daily driver, and having AC for a daily driver is really nice where I'm from. How rare are these trucks with factory AC? More than likely, I'll wind up with a non-ac truck and retrofit AC into it. I was just curious about how rare of an option that was at the time. If I remember correctly, Air conditioning was still a pretty expensive option in the late 60s and early 70s.