To demonstrate the Flores del Mundo membership trends over the course of the year, I would use a line graph to show the overall trend. The reader would be able to get a clear sense of how the data has changed through time. If the total membership was split into two datasets to look at the Eastern and Northern membership over the course of a year, I would still use a line graph to clearly summarize the membership trend and to allow for easy comparison between the two regions.
To graph the total membership vs. employee/spouse/dependent, I would chose a bar graph. When re-reading ‘The Right Graph’ article, the author shows an example of two sets of categorical data which could be used to easily display the total membership in addition to a bar for each subgroup (employee, spouse, or dependent). I would suggest dividing the time into quarters as the author did to ensure the graph is easy to read with the multiple bars at each timepoint.