How many manufactures for the M16 rifle?

Five in the US (Colt, US Ordnance, Harrington & Richardson, GM Hydromatic, and FN Herstal - USA), one in Canada (Diemaco, now known as Colt Canada), one in the Philippines (Elisco), one in the Republic of Korea (Daewoo Heavy Industries), and one in Singapore (ST Kinetics, now known as Chartered Industries of Singapore), for a total of nine manufacturers. Not that these are only the licensed manufacturers - unlicensed copies are manufactured by several companies in the US (referring to actual full auto rifles here, not simply civilian semi auto clones), China, Iran, and the Sudan.