Define a summary field that counts a field in your table that is never empty.
Set up a list view layout based on this same table and add a summary layout part "when sorted by RSVP Status". Put the RSVP Status field and the new summary field in this new layout part.
Find the records you want.
Sort them by RSVP Status to group them by the value in this field.
You will now see a count of the number of records with each status in the sub summary layout part.
IF you don't want to see the individual records listed just above or below this sub summary layout part, remove the body layout part from this layout. (Note: if not correctly sorted, a layout with no body will appear blank until the records are sorted.)