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We study the uniformity of the distribution of compact flat-spectrum AGN onthe sky and the evolution of their relativistic jets with cosmic epoch. Acomplete sample of compact extragalactic radio sources at 15 GHz was recentlycompiled to conduct the MOJAVE program. The MOJAVE sample comprises 133radio-loud flat-spectrum AGN with compact relativistic outflows detected atparsec scales. The source counts of compact AGN shows that the MOJAVE samplerepresents a flux-limited complete sample. Analysis of the population offlat-spectrum quasars of the sample reveals that the pc-scale jets of quasarshave intrinsic luminosities in the range between ~10^24 W/Hz and ~10^27 W/Hzand Lorentz factors distributed between 3 and 30. We find that the apparentspeed (or Lorentz factor) of jets evolves with redshift, increasing from z~0 toz~1 and then falling at higher redshifts (z~2.5) by a factor of 2.5. Theevolution of apparent speeds does not affect significantly the evolution of thebeamed luminosity function of quasars, which is most likely to be dependent onthe evolution of radio luminosity. Furthermore, the beamed radio luminosityfunction suggests that the intrinsic luminosity function of quasars has adouble power-law form: it is flat at low luminosities and steep at highluminosities. There is a positive evolution of quasars at low redshifts (z<0.5)and strong negative evolution at redshifts >1.7 with space density decline upto z~2.5. This implies that the powerful jets were more populous at redshiftsbetween 0.5 and 1.7. We show that the evolution of compact quasars isluminosity dependent and it depends strongly on the speed of the jet suggestingthat there are two distinct populations of quasars with slow and fast jetswhich evolve differently with redshift.Comment: 9 pages, 10 figures, accepted for publication in Astronomy &  Astrophysic

Cosmological evolution of compact AGN at 15 GHz