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

### Instruction:
What is the sum of low estimate(s) that is listed for the date of 1978?

### Inputs:
table_name: table, columns: ['Low Estimate', 'High Estimate', 'Type', 'Location', 'Date']

### Response:
SELECT SUM Low Estimate FROM table WHERE Date = 1978