The index of turnover of construction describes monthly development in the turnover of construction companies. The examined variable is domestic turnover, formed of domestic sales subject to value added tax. The data used for calculating the variable are exclusive of value added tax. In addition, a volume index of sales is produced on construction that measures the development of output in the construction industry. The calculation is based on estimation of change. Sums by industry are calculated using data from the enterprises for which comparable turnover data are available for both the month being examined and for the corresponding month of the previous year. The sums thus obtained are used to calculate annual changes by industry. Calculation of the annual changes also takes into consideration enterprise openings and closures, as well as restructuring and change of activity. The annual changes thus obtained are used to raise the turnover index of the corresponding month of the previous year. The latest index figures may become slightly revised as the volume of data grows and enterprises report changes to their data. Due to supplementations the data will become updated in releases for over twelve months. The statistics and indices compiled from the data are public under the condition that no individual enterprise’s data can be identified from them.