Contemporary market segmentation emerged in the first decades of the twentieth century as marketers responded to two pressing issues. Demographic and purchasing data were available for groups but rarely for individuals and secondly, advertising and distribution channels were available for groups, but rarely for single consumers. Between 1902 and 1910, George B Waldron, working at Mahin's Advertising Agency in the United States used tax registers, city directories, and census data to show advertisers the proportion of educated vs illiterate consumers and the earning capacity of different occupations, etc. in a very early example of simple market segmentation. In 1924 Paul Cherington developed the 'ABCD' household typology; the first socio-demographic segmentation tool. By the 1930s, market researchers such as Ernest Dichter recognised that demographics alone were insufficient to explain different marketing behaviours and began exploring the use of lifestyles, attitudes, values, beliefs and culture to segment markets. With access to group-level data only, brand marketers approached the task from a tactical viewpoint. Thus, segmentation was essentially a brand-driven process.