SELECT MAX("Students") FROM table_19162 WHERE "Pupil/Teacher Ratio" = '20.8'
What is the highest number of students with a teacher:student ratio of 20.8?
CREATE TABLE table_19162 (
    "School Name" text,
    "City" text,
    "Students" real,
    "FTE Teachers" text,
    "Pupil/Teacher Ratio" text,
    "School Level" text,
    "Low Grade" text,
    "High Grade" text
)