text: the Sahara the::ir contribution to the agricuitural labour force is higher or at least equal to the men's contribution. 17. The true dimensions of women's activity are in fact not well measured by <::ctivity rates and proportions since these statistics do not measure total effect.ive work. f-joreover account must be taken of the effective age at which activity begins or ter­ minates. According to the ILO in 1975, 3.6 million young girls of 10 to 14 years of age were economically active in Africa, and they represented sorr.e 16 per cent of the total world economically active populatior. ir. their age group, when Africa's population is only 10 per cent of total world population. These young girls were mair.ly active as family helpers on family farms. Also, the ILO estimated that 1.3 million African women of 65 'years of age or more \'Jere still economically active, representing 2. 6 per cent of total f~n~le labour force, with an activity rate of 19.8 per cent the hi~hest in the world. 18. The women's share of agricultural work is further increased by the effect of urban migration that affects men more than women. 19. t-1any women find themselves de facto if not de jure heads of rural households and cf family -enterprises. Households headed solely by won~n can reach a quarter of all households in countries such as Ker:ya. In the countries bordering the great mining basins of Zimbabwe ancJ South Africa which drain off a large part of the n1i1le population for long periods of time, such house l1olds constitute over 30 per cent of total households. 152 E/ECA/C~.9/5 Table IX.l African population estimates by age and sex in 1975 (Hillions) Ages ------------------------------------65 and Region Sex 0-15 years 15-64 years over Total -----------------------------------------------------------------Africa l-1 plus F. 181 212 13 406 
analysis: The text discusses the contribution of women to the agricultural labor force in Africa, highlighting their significant involvement in agricultural work, particularly in rural areas. It also mentions the impact of urban migration on women's labor force participation and their role as heads of households. The text provides statistical data on the number of economically active women and girls in Africa, as well as their age distribution. The discussion is centered around the economic and social aspects of women's participation in the labor force, specifically in agriculture and rural areas.