How to compare? how many of phone X was sold in its first week and how many of phone Y was sold in its first week. Pretty simple. I'm not sure what the article has for numbers as I go by what I want when I buy a phone (or anything really) and not how many have been sold...
That's the point being made, there doesn't appear to be a source that allows any sort of comparison - how may of X or Y were sold? The article gives neither.