The Green Bay Packers organization is the only one who can sell stock. Once you buy it, you're stuck with it. http://www.onmilwaukee.com/sports/articles/packersstocksale.html
I have been searching also! All I can get for a solid answer would be of season 1960 and to do the math from there....hell let's get the packers hall of fame on this or mybe ESPN on the case and they...
Curly Lambeau, the team's founder, got a sponsorship from a Green Bay meat-packing company, In exchange for paying for the team's uniforms, they got to advertise their company on the team's jerseys....