Proper inclination and proper eccentricity are constants of integration in the theory of secular perturbations of an asteroid. This theory is based on simplified differential equations, and therefore it is not applicable to Hilda-type motion, a case of 3/2 resonance with respect to Jupiter. Numerical integration is necessary for an analogous study of the eccentric Hilda-type orbits. Values of proper eccentricity of real Hildas had resulted from such a study. Here the conditions of nature are approximated stepwise by proceeding from a simplified model to the rigorous problem Sun-Jupiter-Saturn-asteroid. This procedure leads to a way of determining proper inclinations of Hildas. Long-period integrations do not show variations of these characteristic values.