This chapter has the ambition to give information on activity, turnover, employment and number of enterprises involved in construction all over the world.
That suppose reliable statistic information from a lot of sources which have not the same definitions of works or the same methods to collect information.
For instance, a urban land development will involve road, electrical, water supply, wastewater, eventually special foundations, then house building, non residential buildings, etc. The total cost will not necessarily be split into all such items.
So this figures have to be considered with caution. If they are probably rather accurate as a whole, they don't have a great reliability in detail.
As bathing suits, the statistics show a lot of things but hide the most important.