By popular request we've added a new feature which shows the number of Stores that each Filter contains in the search bar of your store locator. This feature works for both Checkbox based Filters and Select Dropdown Filters. Here's how it looks for Checkbox Filters:
And for Select Dropdown Filters:
The filter counts feature also works with Image based Filters.
To enable it, head to your Settings page (http://www.storelocatorwidgets.com/admin/Settings) and set 'Show Filter Counts' to Enabled as shown below: