user: ### NOW ANSWER:
Question: What Year has a Result smaller than 20.31, and a World Rank of 5th?
Columns: ['Year', 'Result', 'World Rank', 'Location', 'Date']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [1972.0, 20.2, '3rd', 'El Paso', 'Apr 15']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Result" < 20.31 AND "World Rank" = '5th';