user: Question: What is the highest rank of a building erected in 1976 with fewer than 21 floors?
Columns: ['Rank', 'Name', 'Height ft / m', 'Floors', 'Year']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1.0, 'Xerox Tower', '443 / 135', 30.0, 1968.0]
SQL:

assistant: SELECT MAX("Rank") FROM "Table" WHERE "Year" = 1976.0 AND "Floors" < 21.0;