How many times songs have been mentioned so far:

A Day in the Life - 5
Yesterday - 5
Here Comes the Sun - 5
Eleanor Rigby - 5
Blackbird - 5
If I Fell - 5

Come Together - 4
In My Life - 3
Here, There and Everywhere - 3
Nowhere Man - 3
Strawberry Fields Forever - 3
Let It Be - 2
You Never Give Me Your Money - 2
Penny Lane - 2
Across the Universe - 2
Tomorrow Never Comes - 2
She's Leaving Home - 2
Hard Days Night - 2
While My Guitar Gently Weeps - 2
Twist and Shout - 2

And 17 more with one mention.