Enquête démographique et de santé, Tschad 1996-97. Demographic and Health Surveys. Calverton, Maryland, USA: Bureau Central du Recensement et Macro International Inc., 1998 Unweighted sample size is less than 25, point estimate, lower limit and upper limit have been suppressed; Unweighted sample size is less than 25, point estimate, lower limit and upper limit have been suppressed