Fever was the thirteenth best selling album of its genre in a country.
 As a result of the methodology that the American and Canadian certification-awarding bodies (the RIAA and Music Canada respectively) use, each disc in a multi-disc set is counted as one unit toward certification, leading to many double albums on the listsuch as Pink Floyd's The Wall and the Beatles' The Beatles (White Album) being certified with a number double the number of copies sold there
In 2022, for sales of albums in 2021, IFPI reported three formats of sales chart, the Global all-format chart which includes all physical sales, digital downloads and streaming numbers, newly created Global vinyl album chart counting vinyl physical sales, combination of physical sales and digital downloads as Global album sales chart

