If you wanted to show the Flores del Mundo membership trends throughout the year, a line graph by month would be the best way to present that data. If you were to break it down by member type (ie. employee, spouse, or dependent), it would be meaningful to do a bar graph by month that is stacked with each member type in a different color. That way, you can easily see how the membership is trending month to month while also visualizing what types of members are making up that data every month.
To compare Eastern vs Northern Membership data, a line graph would also be useful as they would be on the same graph and you can visually see how they compare very easily. You can also look here for monthly trends.