I have questionnaire data that has been collected in 2015 & 2016. However, some of the multi-select options in some questions have changed between years. For example, multi select choices A-C have remained between 2015 & 2016, however 4 new choices D-G have been added in 2016.
How do I analyze this type of question? If I want to show the percent difference between the years for each choice, how would I do this? How do I control for the additional options present in 2016, and absent in 2015?