Wikipedia
Chart-Track
GfK Chart-Track is a market research company that monitors music, videos and software sales in the United Kingdom and Ireland and was formed in 1996. In July 2008, GfK took a majority stake in the company.
The company produces the Official Irish Music Charts and collects data daily from major and independent record stores in Ireland on behalf of the Irish Recorded Music Association. In the UK the company produces the Official UK Software Charts on behalf of UKIE.
Key report services include: UK Leisure Software, UK Hardware and Peripherals, Republic of Ireland Music and Video.