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

### Instruction:
During what years did the tallest building, located at 211 Union Street, have less than 31 floors?

### Inputs:
table_name: table, columns: ['Name', 'Street Address', 'Years as tallest', 'Height ft / m', 'Floors']

### Response:
SELECT Years as tallest FROM table WHERE Floors < 31 AND Street Address = 211 union street