Cosmic ray fluxes in present and past times

The data on primary cosmic ray fluxes at the top of the atmosphere are given for the period since 1937 till the present time. These data have been obtained from the regular cosmic ray flux measurements in the stratosphere and on the ground level. They have been used to find the relationship of cosmic ray fluxes with solar activity (sunspot number). On the basis of the deduced relationship the cosmic ray fluxes in the past have been recovered, as the sunspot number is known since 1500. The link between the smoothed data on Be-10 atom concentrations and cosmic ray fluxes is established which gives a possibility to calculate cosmic ray fluxes in the far past.