Simulated populations of the AGB stars were calculated with different assumptions about mass loss, initial chemical composition and dredge-up efficiency. The early-AGB (E-AGB) phase was taken into account. The numbers of carbon and oxygen stars per 106 generated stars and the ratio (NC/NM) of these numbers were obtained. It is possible to match theoretically obtained NC/NM with the observations only if the luminosity of observed stars Mbol < -3.5; otherwise it is necessary to take into account the E-AGB phase. The data in the Table are for all AGB stars in the Galaxy and for stars with Mbol < -1.80 in the LMC.