I) The case of the US
Album sales in the US are being posted in two distinct formats. The first are sales as we used to know them with download and physical sales at retail of the album combined, this is often named ‘pure album sales’. The second figure posted by Billboard is the SPS, Sales Plus Streaming figure, which encapsulates pure album sales, 1/10 of download sales of all the album songs plus 1/1500 of streaming achieved by those same songs.
Old school chart freaks massively ranted against the second figure, arguing album sales and singles sales can’t be mixed. That’s fundamentally wrong as buyers always purchased songs only – depending on the era, what the available and more worth it format has been, or the album or the single, but in any case the average purchaser was looking for a song nevertheless. Thus, cherry-picking one popular single makes the buying of the full parent album completely useless. If the format is different, the function is the same, buying the song you like no matter if it is packaged with other songs or not, that are unknown anyway. Billboard. thanks to their deep insight of the music industry. fully understood that logic which is why they came out with the SPS methodology.
Still, if some people like their habits it is their choice, so pure album sales keep being posted. Why not? but then, adding them to other figures lacks consistency…