Encuesta de Fecundidad Preferences and motivations in terms of size of the family. Females, between 15-49 years. Females who have had more children than desired reason why they had more children actual age (years). Units: relative figures ;Total;From 15 to 29 years old;From 30 to 39 years old;From 40 to 49 years old; Failure of contraception used;61.57;54.30;72.85;57.77; Lack of knowledge of contraceptions;19.94;4.37;4.04;27.42; Others;23.92;41.33;27.66;21.03; Notes: Source: National Statistics Institute