I think that a line graph would be the best option for showing Flores del Mundo’s membership trends over the course of the year. This is a time series relationship, and so creating a line graph with time in months on the x-axis and number of members on the y-axis would enable viewers to easily see the trends in membership over the course of the year. I would also use a line graph to depict the Eastern and Northern regions on the same graph, with a separate line for each region.
As others have noted, the best option for graphing total membership versus employee/spouse/dependent depends on the intervals of time used. If I wanted to show the overall breakdown for the entire year, I would create a bar graph with a categorical x-axis for each member type, and the number of members on the y-axis. This allows for a quick comparison across member types. If I wanted to show the trends in membership over time for each of these categories, I would use a stacked bar graph, but would likely use larger time intervals like quarters instead of months to reduce visual clutter (as others have suggested).