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

### Instruction:
What is the total number of quantity when the introductory year was 1984?

### Inputs:
table_name: table, columns: ['Manufacturer', 'Model', 'Quantity', 'Introduced', 'Retired']

### Response:
SELECT SUM Quantity FROM table WHERE Introduced = 1984