From the year 2010 all information in the statistics are comparable over time. The statistics can be compared to general enterprise statistics, account statistics, International trade in goods, Production and turnover in manufacturing industries and Retail trade index. There are differences in definitions regarding these statistics which influence the reported figures. These definitions include which types of sale/turnover which is included and the minimum size of included firms.
The statistics is made on the basis of Eurostat guidelines and is hence comparable to statistics from other EU countries under same regulation. The groupings 4-8 of the 10-standard-grouping are published as a national index on the Eurostat homepage.
VAT (value added tax) was introduced in Denmark in 1967, and the administrative information on the tax system was primarily used as a source for compiling quarterly statistics on VAT and turnover in non-agricultural industries, which were published for the first time as from the first quarter of 1968. After 1982 the VAT amounts were dropped from the statistics, which were consequently renamed Turnover in non-agricultural industries.
Starting with January 2001 the statistics became monthly, the statistical reference unit was changed from the VAT-reporting unit to the legal unit (corporation/enterprise/firm), and the agricultural sector was included, hence the title Purchases and Sales by Firms.
In the statistics there has not been information on purchases total and sale total for the period January 2010 to April 2012. This means that the statistics has only included domestic purchases and domestic sales - and not the import and export. The background for this to be left out was that total sales during 2010 had a development that could not be found in other statistics. The development of export etc. based on the VAT declarations deviant from the export from the balance of payments, which led to purchases total and sales total not to be published can also be found in the current data. It must primarily be ascribed to a change in the content of the spaces of the VAT form, and a change in the behavior of firms.
The current monthly statistics for purchases and sales of firms start with data for January 2009. The new published data from 2009 are primarily based on a mechanical computation of the business's VAT declarations. Very large errors are corrected - often after having been in contact with the firm.
Break in series between 2009 and 2010: From 1. January 2010 export of services is reverse charge (excl. VAT), while this was payable to VAT in Denmark prior to this, and thereby it was part of domestic sales; equivalently for import of services. This results in a break in series in the VAT from 2009 to 2010.
Figures from the General enterprise statistics, Account statistics, International trade in goods, Production and turnover in manufacturing industries and Retail trade index can be compared to the figures of this statistics. There are differences in definitions regarding these statistics which influence the reported figures. These definitions include which types of sale/turnover which is included and the minimum size of included firms.
Data is collected from a single source: The Danish tax authorities "SKAT". Hence no data integration is performed from different sources/registries and the sources of the statistics are therefore consistent. Units and groups in the statistics are treated in the same way both at "SKAT" and Statistics Denmark, and the data set is thus consistent. A given unit/grouping will appear in the same way in all published tables so that output data is also consistent.