Hitlisten

Hitlisten, also known as Tracklisten, is a Danish top 40 record chart that is updated every Thursday midnight on the website hitlisten.nu. The weekly Danish singles chart Track Top-40 combines the 40 best-selling tracks from legal music downloads and the sales of music singles on either CD or vinyl. The data are collected by Nielsen Music Control, who also compile the chart on behalf of IFPI (International Federation of the Phonographic Industry).
1965–1993: early IFPI charts.
This chart began in April 1965 as a monthly top 20 chart compiled by the Danish branch of the International Federation of the Phonographic Industry (IFPI). It was published in several major Danish newspapers. Prior to that several Danish charts were compiled by competing newspapers.
From April 1969 it went weekly after Denmark's Radio stopped publishing their weekly top 20 chart. 
From May 1973 to December 1978 singles and albums were presented on the same chart due to a request from Denmark's Radio for variety in their chart show. During this period only few singles reached the top. The formats were finally split again in January 1979.
1993–2001: Nielsen Music Control and IFPI.
Danish IFPI continued producing single charts in the 1980s and 1990s even though not many singles were sold. Prior to 1993, Denmark was the only market in Scandinavia without a fully recognized and reliable airplay chart. In January 1993, "Music & Media" announced that IFPI Denmark was moving towards launching a national airplay chart through collaboration with AC Nielsen. Beginning in 1993, Danish charts were compiled by Nielsen Music Control (originally AC Nielsen).
2001–2007: Hitlisten.
The Danish Singles Chart Hitlisten consisting of Single Top-20 and Download Top 20 was relaunched 1 January 2001 and served as official chart for Danish record sales until end of October 2007.
2007–present: Tracklisten/Hitlisten.
The track list was established on 2 November 2007 replacing the Hitlisten charts that were discontinued end of October 2007. The chart is supervised by IFPI Denmark and contains three charts:
Hitlisten also continues to publish specialised charts:
Track list was also updated back to week 1, 2007, thus creating an overlap of sometimes differing chart #1s between Hitlisten and Tracklisten for the period 1 January 2007 and 2 November 2007 (weeks 1 to 42 / 2007). For this period, the Hitlisten charts continue to be considered as the official charts for singles record sales.