I currently have a stacked bar chart that has an x-axis of time in months, and a y-axis in count of reports with multiple categories ranging from 1-12. I am looking to try and create a dual axis chart with the left axis still showing the count of reports and the right axis showing the percent difference from the previous month as a line chart. A key issue I am having is that I am only interested in seeing the percent difference in categories of 7 and over. I have found the quick table calculation that will allow me to show the percentage change from previous month, but I am having trouble showing it only on categories of 7+.
To recap, it is a dual axis chart. Left axis shows count of reports in a stacked bar chart with all 1-12 categories. Right axis will show percent change from previous month as a line chart for categories only 7-12