Conversation so far:
What year did Johnny Carson's The Tonight Show move to Burbank?
On May 1, 1972, The Tonight Show moved from 30 Rockefeller Plaza to Burbank, California, because of the studio's proximity to celebrities.
What did Johnny Carson host in Burbank?
Johnny Carson hosted The Tonight Show in Burbank.

Question: How often was his show on?
Self-contained rewrite: How often was the Tonight Show starrring Johnny Carson on?