National tables: age and sex. Values Age at first sexual relationship in persons of 18 to 49 years by sex, age group and type of indicator. Units: ? ,Total,,From 18 to 29 years of age,,From 30 to 39 years of age,,From 40 to 49 years of age,, ,Average,Standard deviation,Average,Standard deviation,Average,Standard deviation,Average,Standard deviation, Both sexes,18.6,3.3,17.8,2.6,18.8,3.4,19.3,3.7, Males,18.1,3.3,17.5,2.6,18.2,3.3,18.8,3.9, Females,19.1,3.2,18.2,2.5,19.4,3.4,19.8,3.3, Notes: Data corresponding to cells with less than 45,000 persons must be used with caution, because they may be affected by high sample errors. Source: National Statistics Institute