P vs l

P

character

  • The sixteenth letter of the English alphabet, called pee and written in the Latin script. 

name

  • The set of all problems that are solvable in polynomial time by a deterministic Turing machine 

noun

  • A P wave on an electrocardiogram. 

l

character

  • The twelfth letter of the English alphabet, called el and written in the Latin script. 

How often have the words P and l occurred in a corpus of books? (source: Google Ngram Viewer )