Thermodynamic data were used to calculate the Kirkwood-Buff integrals for the aqueous solutions of methanol, ethanol, propanols, and butanols, The calculated values have been compared to those obtained from small-angle X-ray scattering (SAXS) experiments, and satisfactory agreement was found. Improved expressions have been suggested and used to calculate the excess number of molecules around central ones. On this basis, information about the structure of the solutions was gathered, the main conclusion being that the interactions among similar molecules prevail; this leads to clustering dominated by the same kind of molecules.