Sampling errors Males who have had sexual relationships in the last year. Variation coefficient by age group and use of a prostitute in the last year. Units: % ,Total,Yes,No, Total,1.47,6.89,1.58, From 18 to 29 years of age,2.40,10.56,2.47, From 30 to 39 years of age,2.62,10.04,2.74, From 40 to 49 years of age,2.79,13.68,2.97, Notes: Source: National Statistics Institute