First of all, props for using the word "bucketize" in a sentence!
Second of all, you really should attach a packaged workbook so the community can review your progress so far and validate any proposed solution that we provide you. Since this is EPA data, it should be in the public domain, and you should not need to anonymize your workbook before posting it.
Now… without having seen your workbook, I would say that likely the most straightforward solution will be a simple aggregation in conjunction with conditional value materialization. Something like this:
SUM( IF [Year] >= 2009 AND [Year] <= 2014 THEN [Amount] END ) / SUM( IF [Year] = 2000 THEN [Amount] END ) - 1
This simple aggregation will compute over whatever level of detail is on your view, so if you put [State] on the Filters or Rows shelf, it will compute it for each state.
Hope that helps. If you have any more questions, I strongly encourage you to post your workbook (as a TWBX packaged workbook) so we can take a closer look at your work.