The amount of chlorine produced is directly proportional to the amperage drawn at each electrolytic cell. The amount of electric current required to generate one mole of chlorine, (Cl2, -70.906g), or its equivalent in chlorine compounds after hydrolysis, is calculated as follows:

a) One mole chlorine Cl2 requires 2 faradays of electrons flowing. 
2 faradays = 2 x 96,500 coulombs.
b) 1 coulomb = 1 Amp/second. Therefore 2 faradays equals:
2 x 96,500A/sec  = 193.000  = 53.6111 A/hr 3,600
c) Therefore 1 gram Cl2 is generated by
53.6111 = 0.756087 A, OR 1A = 1.3226 g Cl2/hr 70.906

These calculations assume a 100% cell efficiency. In reality a number of competing reactions take place. Cell losses, varying electrolyte conductivity, impurities etc., reduce cell efficiencies to in the region of 70% to 90%. A number of wide ranging variables such as water chemistry, cell design, ohmic losses and other factors ultimately dictate the chlorine production in each particular application.