User:Muhandes/Certification Table Entry/Sales/DanishPeriod/doc

This helper template calculates periods for Danish certifications, as stated in the following sources.

First, since until June 2012 certifications were based on release data. Since July 2012 certifications are based on certification date. It is assumed that if no certification date is provided, or certification date is unclear, certifications are based on release date.

Following this decision, the thresholds are according to periods:


 * - levels changed in April 2003
 * - new levels for albums and singles in February 2007
 * - new levels for singles active in September 2010
 * - new albums levels change in 7 January 2011
 * - new single levels from 17 November 2014
 * - new single levels from 1 April 2016

It returns:

Returns 0 if the data provided is not sufficient.