We represent a new solution of the set of equations describing laser cooling of atoms by velocity selective coherent population tapping. Our solution is valid at large interaction time t in a full range of atomic kinetic momenta. Referring to this analytic expression we obtain the formula for lowest achievable temperature of cooled atoms for given experimental conditions. We demonstrate that the cooling efficiency decreases as t -3/4, when t is greater than or equal to (Gamma) 12-1, where (Gamma) 12 is the low-frequency atomic coherence decay rate. Also the case of subrecoil laser cooling in vertical direction is examined and the gravitational force influence is estimated.