We live in an affluent, well-educated neighborhood, like the OP. By my own calculations, the G&T program at our school included 3% of the students before the appeals process began, and after appeals, 5%. The way our "selection" matrix is written, the number of gifted will vary every year, depending upon how many qualify.
The program seems limited (it is not a "magnet" addressing all subjects, just a class that meets daily), but it seems light years better than what we had before programming started. We consider ourselves fortunate.
Our state has no mandated gifted education.