The spectrum features of UHECRs below and surrounding GZK

The energy spectrum of ultra-high energy cosmic rays (UHECRs) is discussed on the basis of the Yakutsk array database analysis. In the region E-0 = 10(17) to 3 x 10(19) eV the showers are detected under trigger-500, while at energies above 3 x 1019 eV the whole acceptance area for trigger-1000 is used in order to utilize all the data available in the region of Greisen-Zatsepin-Kuzmin (GZK) cutoff. Updated relations are adapted to estimate the primary energy having detected densities of charged particles at the distance 300/600 m from the shower axis.