If this was a high school overnight homework assignment, at best I'd give it a B+. 
This author does not indicate if he/she is referring to the calendar year or fiscal year this the 2012 and 2015 comparison. And I think he/she meant to say that the 93% decline in revenue was from $6.1 billion to $400 million not $4 billion as that is only 35% decline. 

So there are errors(actually for your point of view). And none of this information should be any kind surprise to anyone.