Sampling errors Persons who have had casual partners in the last year. Variation coefficient by age group and sex. Units: % ;Both sexes;Males;Females; Total;2.91;3.25;5.60; From 18 to 29 years of age;3.84;4.22;7.22; From 30 to 39 years of age;5.45;5.95;12.09; From 40 to 49 years of age;6.71;7.99;12.82; Notes: Source: National Statistics Institute