Sorry,I am late...I went to Mexico City for business for a few days.
Butcher and GSP are both right,color developed film has no silver...all silver remains in fixer,all what you see in a colour negative are dyes.
To process undeveloped film to recover silver just dip the negatives onto fixer(sodium/ammonium thiosulfate) and recover silver using electrolysis,zinc/HCl,sodim sulfide processes.
Silver content in films has been posted by GSP,for some other kind of films(like 400,800 and 1600 ASA or 4x5,5x7 and 8x10 plates) you can obtain that information on the "J Series",by Eastman Kodak,I have posted.
I hope it helps.
Kindest regards.
Manuel