Herein lies the true advantage of the radiocarbon method, it is able to be uniformly applied throughout the world.
There is a useful diagrammatic representation of this process given here Libby, Anderson and Arnold (1949) were the first to measure the rate of this decay.
They found that after 5568 years, half the C14 in the original sample will have decayed and after another 5568 years, half of that remaining material will have decayed, and so on (see figure 1 below).
Renfrew (1973) called it 'the radiocarbon revolution' in describing its impact upon the human sciences.
Oakley (1979) suggested its development meant an almost complete re-writing of the evolution and cultural emergence of the human species.
These isotopes are present in the following amounts C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%.