What percentage of old firm fans are bigoted scum ?
There is no real way to assess this and assign a percentage. Sectarianism is not as rife in the modern game anymore due to tough crackdowns by both sides of the old firm. Also both teams now attract a more multi cultural set of fans from all backgrounds, for example the increase of Japanese Celtic fans, and such fans have no idea about the problems of sectarianism. They are simply there to support the club on a footballing basis. There are a lot more fans of both sides also that will not put up with bigots during matches and bring the bigoted individuals to the attention of police and stewards who promptly remove the individuals from the ground.