A correction has been made to Table 3.4a - Number of firms by size and trade of firm. In the ‘Civil engineering’ column under the ‘Main trades’ heading, the number of civil engineering firms in size bands 4-7 to 8-13 has been changed to 3,646 from 3,464. In the same column, the number for size bands 14-24 to 1,200+ has been amended to 1,541 from 5,187. The column total has been amended to 21,257 from 24,721. We apologise for any inconvenience.