extended family groups sharing a single household enjoy specific advantages, such as a greater sense of security and belonging due to sharing a wider pool of members to serve as resources during a crisis, and more role models to help perpetuate desired behavior and cultural values. However, even in cultures in which adults are expected to leave home after marriage to begin their own nuclear-based households, the extended family often forms an important support network offering similar advantages. Particularly in working-class communities, grown children tend to establish their own households within the same general area as their parents, aunts, uncles, and grandparents. These extended family members tend to gather often for family events and to feel responsible for helping and supporting one another, both emotionally and financially. While contemporary families may be considered more mobile in general than in the past, sociologists find that this has not necessarily resulted in the disintegration of extended family networks. Rather, technological aids such as the Internet and social networking sites such as Facebook are now commonly used to retain contact and maintain these family ties. Particularly in the case of single-parent households, it can be helpful for extended family members to share a single household in order to share the burden of meeting expenses. On the other hand, sharing a household can present a disadvantage depending on the sizes and number of families involved, particularly when only a few members shoulder most of the responsibility to meet expenses for the family's basic needs. An estimated 49 million Americans (16.1% of the total population) live in homes comprising three or more generations, up from 42 million in 2000. This situation is similar in Western Europe. Another 34 percent live within a kilometer of their children. Around the world In many cultures, such as in those of Asians, Middle Easterners, Africans, Indigenous peoples like Native Americans and Pacific Islanders, and Latin Americans and Caribbeans, even for Eastern Europeans and Southern Europeans (Orthodox/Catholic countries), extended families are the basic family unit. That is to say the modern western nuclear family is not the norm. Even in Western Europe, extended families (mostly of the stem type) were also clearly prevalent, England being a rare exception. In Britain and the United States, during the Industrial Revolution (approximately 1750 to 1900), more people lived in extended families than at any time before or since. It is common for today's