Documentation of statistics: Business Services in the Sector for Market Research and Public Opinion Polling
grossed up in part by including information turnover from the Accounts Statistics for Non-Agricultural Private Sector in the reference year for the entire population
https://www.dst.dk/en/Statistik/dokumentation/documentationofstatistics/business-services-in-the-sector-for-market-research-and-public-opinion-polling
Documentation of statistics