At the national level, however, the publication of statistical data serves to make law enforcement work transparent and allows for the indication of at least certain trends in the application of interception measures. The obligation to collect and report statistics on communications interception exists in Germany, Belgium, France and Sweden. National reporters from the United Kingdom and the Czech Republic indicated that, although there is no legally established duty for law enforcement to collect statistics, data is publicly available, eg., in the United Kingdom, the number of warrants is reported for both police and security services by the respective commissioners. In the Czech Republic, despite the absence of such an obligation in the law, the police are required under internal regulations to publish analytical and statistical information, including data on the interception of communications. Some of the country reports, like that from Belgium, also referred to statistics in the transparency and disclosure reports from electronic communications service providers, e.g., Google, Vodafone, Microsoft, etc., as to the assessment of the number of requests coming from law enforcement agencies. Spain is the only country where such a reporting obligation does not exist and statistical data are not currently available to the public.
(Comparative Analysis în Access to Telecomunication Data in Criminal Justice (coord. U. Sieber, N. von zur Muhlen), Duncker & Humblot, decembrie 2016, la p. 22)