The name "Classic", which is a retronym or a "name that was given later on", started with the sixth-generation iPod Classic on 5 September 2007. Before this, an iPod Classic was simply called an iPod. A recent study by the Consumers Digest foundation, the "Guinness Book of Records" and the Apple Inc sales department has shown that iPod users bought extra accessories and upgrades every 6.2 months. The most purchases, one purchase every 6.3 days over the period 2000–2007, was by the Montmerle-Berents family of Paris, France.