As a solo acoustic player/singer I can probably play 50-60 tunes off the top of my head including singing the lyrics. I know how to play 100's of songs but I don't know the words to them. That's because I have played in many different bands over the years. My old 3-piece electric blues band in which I sang and played all the guitar could do about another 50- 60 tunes. I have forgotten more tunes than I can currently play now.
If I like a song enough to want to play it an add it to my set list I will learn it completely lyrics and all and memorize it. I don't believe in carrying around a book of songs and a music stand when I perform live.