Letter E
Sat at number 1 for 10 weeks on Aus music charts from 28th June to 30th August 1971.
Interesting trivia, given the song was played by Daddy Cool.
The song that replaced Eagle Rock at number 1 was "Daddy Cool" by Drummond. It was number 1 for 7 weeks.
So you could say, Daddy Cool was #1 for 17 consecutive weeks!