When did cartridge revolvers begin to outnumber cap and ball ones in the hands of civilians?

I know that the U.S. military started using cartridge revolvers in 1870, but when did they start becoming more common than cap and ball ones in the civilian market?

I know that the U.S. military started using cartridge revolvers in 1870, but when did they start becoming more common than cap and ball ones in the civilian market?