Concerns have been raisedabout the decreased ability of Wikipedia to recruit editors and in to harness the effort of contributors to create new articles and improve existing articles. But, as Marwell & Oliver explained,in collective projects, in the initial stage of the project, people are few and efforts costly; in the diffusion phase, the number of participants grows as their efforts are rewarding; and in the mature phase, some inefficiency may appear as the number of contributors is more than the work requires. In this paper, thanks to original data we extract from 36 of the main language projects, we compare the efficiency of Wikipedia projects in different languages and at different states of development to examine this effect.