  The paper presents the phenomenological analysis of the energy dependence for
the ratio of elastic to total cross section in proton-proton and
antiproton-proton scattering. The analytic functions based on the study of low-
and high-energy experimental data for various scattering parameters provide the
quantitative description of energy dependence of the ratio with statistically
acceptable qualities in wide range of collision energy $\sqrt{s} \geq 3$ GeV in
the case of the separate datasets for $pp$, $\bar{p}p$ collisions and at
$\sqrt{s} \geq 5$ GeV for the joined experimental data ensemble. Based on the
fit results the estimations are derived for the ratio of elastic to total cross
section in $pp$ scattering at various $\sqrt{s}$ up to energy frontier
$\sqrt{s}=10$ PeV which can be useful for present and future hadron colliders
as well as for cosmic ray measurements at ultra-high energies. The indication
is observed for onset of the asymptotic region at $\sqrt{s} \gtrsim 5-10$ PeV
for the ratio of cross sections under consideration.
