High quality single crystals of Bi-2212, Tl-2212 and Tl-2223 were studied using X-ray photoelectron spectroscopy. From a deconvolution of the Cu2p 3/2 main line, we have shown that the density of O 2p holes in the Cu-O planes are qualitatively similar in case of the Bi and Tl-2212 systems even though they have shown many other differences in their electronic structure properties. Also the results show a dependence of the density of holes on the number of Cu-O planes as we go from Tl-2212 to Tl-2223.