Fig.20 Demographic characteristics available on UNHCR’s population of concern | 2008 - 2015 Population size (millions) Total Pop. of concern Sex-disaggregated data available Age-disaggregated data available 60 50 40 30 20 10 0 2006 2007 2008 2009 2010 In turn, uneven availability of disaggregated data presents an important limitation to comparative analysis between locations and populations, and over time. UNHCR continues to remind countries and datacollecting agents within the humanitarian community of the importance of disaggregated data by location and demographic characteristics. Demographic Characteristics In 2015, 164 countries provided demographic information disaggregated by sex, the same number as the previous year. Of the total population of concern at the end of 2015, data disaggregated by sex was available for 29.3 million – 46 per cent of the total population of concern to UNHCR. Of the data available on sex at the end of 2015, females and males accounted for 14.3 million and 15.0 million people, respectively. Information disaggregated by age was less complete, as fewer countries provide such data. Only 141 countries provided age-disaggregated data at the end of 2015, although the coverage of such data has increased over time Figure 20 . Data disaggregated by age were available for 21.2 million people (33%) at the end of 2015, compared to 17.0 million people at the end of 2014. Of the 21.2 million people covered by age-disaggregated data, 51 per cent (10.9 million) were children. The demographic characteristics of refugee populations have fluctuated over the past 10 years. The proportion of women among refugees ranged between 47 per cent and 49 per cent from 2003 to 2015, while that of children has ranged more widely, from 41 per cent in 2009 to 51 per cent in 2015 Table 5 . The proportion of refugee populations in what is defined as the working-age group (aged 18-59) saw a high of 52 UNHCR Global Trends 2015 2011 2012 2013 2014 2015 54 per cent in 2009 versus 47 per cent in 2015. The older refugee population group (60 years and older) has varied by a few percentage points since 2003, between 5 per cent in 2003 and 3 per cent in 2015. At the end of 2015, age-disaggregated data were available for 9.6 million refugees (out of the 16.1 million total refugee population), compared to 8.4 million IDPs (out of the total 37.5 million IDPs). The proportions of sex-disaggregated data for the types of population of concern reported to UNHCR were as follows: returned IDPs (91%), others of concern (84%), refugees (71%), returned refugees (66%), stateless persons (46%), asylum-seekers (42%), and IDPs (33%). Location Characteristics The characteristics of the places where refugees and others are living are as important as these populations’ demographic characteristics. In order to ensure uniformity and comparison across all geographic regions, the available location data of refugees are classified into three main groups: urban, rural, and various/unknown (this latter including locations that are a mix of urban and rural, or are unclear). Recognizing the differences in national definitions and classifications of ‘urban’ and ‘rural��, UNHCR maintains a common approach for data collection across different geographic regions and locations. Type of accommodation is useful information to improve the efficient allocation of resources, review policies, and design programmes. Accommodation type is classified into six categories: planned/managed camp, self-settled camp, collective centre, reception/transit camp, individual accommodation (private), and various/ unknown if the information is unknown or unclear. Each of these types can be in either urban or rural locations.