 The skewed male–female ratio is probably an artifact of the differential between male and female lifespans in Lithuania (male average lifespan in Lithuania was 66 years in 2004, as against 78 for females), according to the World Health Organization.At the time of the 2001 census, persons aged between 0 and 15 years comprised 16.1% of Žirmūnai's population, the second lowest percentage among Vilnius' elderates, slightly higher than Viršuliškės at 15.5%.However, it is likely that the average age of Žirmūnai's residents has decreased since the last census, and will continue to decrease, as a result of the active construction of new dwellings, which are acquired primarily by younger people.