Old Trafford, with undeveloped countryside separating them. During the 19th century, the sections merged. The western terminus of the early medieval linear earthwork Nico Ditch is in Hough Moss, just to the east of Stretford; it was probably used as an administrative boundary and dates from the 8th or 9th century. Demography As at the 2011 UK census, the Stretford area wards of Clifford, Gorse Hill, Longford and Stretford had a total population of 46,910 and a population density of 8,907 persons per square mile (3,439 per km2). Stretford residents had an average age of 36 years, younger than the 39.3 Trafford average. For every 100 females, there were 97.8 males. Of all residents, 42% were single (never married): in Trafford, 33% were single. Of the 19,209 households, 33% were one-person households, 56% were married couples with dependent children, and 15% were lone parents with dependent children. Of those aged 16–74 in Stretford, 23% had no academic qualifications, higher than the 18% in all of Trafford. With 78% of residents born in the United Kingdom, there is a relatively high proportion of foreign-born residents reported. There is also a high proportion of non-white people, as 63% of residents were recorded as white. The largest minority group was Asian, at 21% of the population. In 1931, 19% of Stretford's population was middle class and 20% working class compared to 14% middle class and 36% working class nationally. The rest of the population was made up of clerical workers and skilled manual workers. By 1971, the middle class in Stretford had declined steadily to 15% whilst the working class had grown to 31% compared to 24% middle class and 26% working class nationally. Economy Until the end of the 19th century Stretford was a largely agricultural village. The development of the Trafford Park industrial estate in the north of the town, beginning in the late 19th century, had a significant effect on Stretford's subsequent development. At its peak in 1945 the park employed an estimated 75,000 workers; housing and other amenities had to be constructed on what had previously been agricultural land. Trafford Park is still a very significant source of employment, containing an estimated 1,400 companies and employing about 44,000 people. The main shopping centre is Stretford Mall in the commercial centre of Stretford, previously known as Stretford Arndale. It was opened in 1969 and changed its name in 2003. It