Yes, I just searched Neilson ratings on Google. There a quite a few sites that give ratings for the Columbo years, some by the week. Its depressing to recall so many excellent shows, compared to the trash that is on today. Or are trash at least in my opinion.

I am a big Columbo fan and saw the first runs, but I don't remember what day of the week they were aired. I think Columbo was part of the NBC Saturday Night Movie rotation. A few of the lists do not list Columbo but NBC Sat Movie.

Columbo originally aired Sunday nights once a month as part of the NBC Mystery Night movie along with McMillan and Wife, McLeod and Hec Ramsey.