Looking at the Mexico numbers which are to close to 7%, it makes sense why they are in a separate category with it's own Priority Dates.
Now not only DR exceeded 7%, it almost went twice as much and more than what I tabulated.
It's not surprising at what explanation you put in if months after months you are getting 1200-1500 visas per month on F2B.
Also take out that 13,690 F2B from DR and most of us would probably be receiving our interview letter by now.