Template:Certification Table Entry/Sales/BelgianPeriod/doc

This helper template calculates periods for Belgian certifications, as detailed here. The sources used are:


 * Album change in May 2007
 * Latest certain date for singles "old" levels October 2007
 * First certain date for singles "new" levels June 2009 ,
 * 2016 singles change, July 2017 albums change
 * July 2018 singles change

It returns:

Returns 0 if the data provided is insufficient