I think a lot more detail needs to be given here.

First off, what is being measured? Wood burning emits C02. If you were to specify that this is for *nonrenewable* emissions then it would be better.

Second, are the income groups static? Or do they change over time? And at what point in time are they composed from? High income as of 2023? High Income as of 1990?

Third, how large are each of these groups?