Detected radio emission from galaxies is largely synchrotron emission, which is created when charged particles move with relativistic velocities inside a magnetic field. Depending on the process that is causing this emission, sources can be separated into two distinct populations. The first population are galaxies that have active galactic nuclei (AGN galaxies). The second population are star-forming galaxies (SF). Both populations are detected via radio sky surveys and categorized in source catalogues. The easiest way to process data from a catalogue is simply counting the sources. Differential source counts are defined as number of sources per unit flux density per unit solid angle. Differential source counts can also be obtained from luminosity functions. Luminosity functions give the number density of objects inside a predefined interval of luminosity. Luminosity functions depend on the cosmological redshift and it can be said that they evolve. In this paper, differential source counts for two previously mentioned populations are obtained using predefined analytical models of evolving luminosity functions. Differential source counts are also obtained from data taken from various catalogues. Results obtained from analytical models and from data are well constrained within the uncertainty of the calculation. Differential source counts are dominated by AGN galaxies at highest values of flux density. Equal contribution to the differential source counts from both types of sources is found at flux density values of 200 μJy. Below 10 μJy the fraction of SF galaxies is higher than 90% as they dominate differential source counts at these values of flux density.