In this activity the historical dynamics of life-span distribution parameters of the people was investigated in 12 developed countries encompassing the period of 1750-1998 years, it is treated about 1200 life tables. The approximately of a linear segment of a curve of age-specific death rate by the Gompertz function allows getting an analytical view of the life-span distribution. It is shown that the decreasing of the lower age range since 35 years till 10 years a little bit augments an approximation error. The Stehler-Mildvan correlation parameters are computed for each country, for each year during all indicated period. Estimations of the average life, modal age, dispersion etc. are obtained. It draws a conclusion about the limitation and stabilization of modal age at preservation of existing regularity in dynamics of the life-span distribution parameters.