Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Of 2010 est. with less than 171,750 and 2000 less than 131,714, what is the 1970 population average?

### Inputs:
table_name: table, columns: ['City', '1970', '1980', '1990', '2000', '2010 est.']

### Response:
SELECT AVG 1970 FROM table WHERE 2010 est. = 171,750 AND 2000 < 131,714