How to interpret correctly this chart about nitrogen oxide?
A person answered to me on a dedicated Facebook group. He suggests that the labels are about areas, not lines, so the grey area (emissions in Sweden), is only the visible area, it does not continue below the dark area (emissions abroad). I find this representation very confusing.

As an example, the emissions in Sweden in 2008 are 225 - 100 = 125, the difference between the total and the dark area, and not 100 as I thought.

This way, the correct answer is 1100, because the upper line already represents the total emissions, and between 2004 and 2008 we have an average of 225 for 5 years.