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

### Instruction:
What was the Attendance on December 21, 1986 before Week 16?

### Inputs:
table_name: table, columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']

### Response:
SELECT SUM Attendance FROM table WHERE Date = december 21, 1986 AND Week < 16