About a third of the soldiers worked as common labourers in civilian life, while almost a fifth worked as handweavers, a tenth cobblers, and a twentieth tailors. Another analysis, this time of British soldiers stationed in North America during American Revolutionary War, found that a consistent link existed between recruitment and regional economic conditions in Britain. A higher proportion of recruits came from areas particularly vulnerable to economic cyclical fluctuations than areas with a stable economy. Most army recruits found themselves either permanently or temporarily outside the labour market because of the structural changes of the British economy that came with the industrial revolution. A fifth of the recruits either worked as textile workers or had had some other connection with the textile industry. Among recruits with a background as craftsmen, the trades affected negatively by industrialization, such as shoemakers, dominated. Trades with marked seasonal fluctuations in employment, including bricklayers and stone masons, also provided the army with many recruits. Socially and economically stable working class occupations (miners, ironworks workers, or nailors for example) supplied very few soldiers. Non-commissioned officers Non-commissioned officers in the infantry were sergeants and corporals. In addition to the direct leadership of the rank and file entrusted them, the commissioned officers happily surrendered the routine administration of the companies and regiments to the sergeants. Senior non-commissioned posts, such as colour sergeant, introduced in 1813, and sergeant major, were strictly speaking not ranks, but appointments. Appointment as sergeant major was the capstone of a successful career as non-commissioned officer, symbolised by an officer like uniform. Selection for this post was based on capability as a drill instructor, but to the same extent also of skills at writing and counting. No special pattern for promotion to non-commissioned officer has been found. Literacy was a basic requirement and surprisingly many were promoted to sergeants after just one year of service. In the cavalry, the circumstances were somewhat different. Until 1810, when it was replaced by rank of troop sergeant major, each troop of horse had a troop quartermaster, a rank between commissioned and non-commissioned officer. During the eighteenth century, this rank began to be increasingly seen as suitable for promoted sergeants. Nevertheless, the rank was attractive enough for poor young gentlemen who could not afford to purchase a proper officer's commission. Warrants as troop quartermaster could sometimes be purchased, although George II did not like to commission troop quartermasters.