A detailed statistical description of evolution of supersaturated-by-gas solution at degassing has been presented on the basis of finding the time-dependent distribution in radii of overcritical gas bubbles. The influence of solution viscosity and capillarity via internal pressure in the bubbles on this distribution has been considered until the moment when the gas supersaturation drops due to depletion and stops nucleation of new overcritical gas bubbles. This study is based on our recent semi-analytical approach (A.E. Kuchma, A.K. Shchekin, J. Chem. Phys. 154, 144101 (2021) and A.K. Shchekin, A.E. Kuchma, E.V. Aksenova, Physica A 609, 128303 (2023)) to the problem of finding the nonstationary growth rate of overcritical bubbles in dependence on gas supersaturation, on diffusivity and solubility in solution, solution viscosity, surface tension on bubble surface. Other important factors are linked with the initial rate of homogeneous gas-bubble nucleation and coupling between diffusivity and viscosity in the solution. Here we numerically studied how all these factors affect the time-dependent distribution function of overcritical bubbles in their radii, maximal and mean bubble radii and the time-dependent swelling ratio of a supersaturated-by-gas solution in a wide range of solution viscosities.