Thunno, \$ 18 \log_{256}(96) \approx \$ 14.82 bytes
34C"34C+sc9/"+sc9/
Based off @Mukundan314's Pyth answer.
Thunno, \$ 6 \log_{256}(96) \approx \$ 4.94 bytes
zdsc6/
Probably cheating but I'll put it here anyway.
ExplanationExplanations
34C # Push chr(34), the double quote
"34C+sc9/"+ # Prepend it to the string "34C+sc9/"
sc # Swap and count the number of times the input is in the string
9/ # Divide by 9 (Half the length of the program)
zd # Push the source code
sc # Swap and count the number of times the input is in the string
6/ # Divide by 6 (The length of the program)