Considering the period since the early 1990s, only three countries in the group (Benin, Central African Republic and Mali) have managed to double labour productivity. Major factors impeding significant improvements in agricultural labour productivity have been the low level of rural human capital, the slow accumulation thereof in many of these countries and the low level of conventional inputs (apart from land and labour) to agricultural production. Low levels of education and literacy, and poor health, also limit technical efficiency.