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

### Instruction:
How many values of attendance occur when ave. on previous season is +645?

### Inputs:
table_name: table, columns: ['Season', 'Ave. Attendance', '+/- ave. on prev. season', 'Competition', 'Occupier']

### Response:
SELECT COUNT Ave. Attendance FROM table WHERE +/- ave. on prev. season = +645